pLLLLSSSS HELPP IM MARKING BRAINLIEST
The water usage at a car wash is modeled by the equation W(x) = 3x3 + 4x2 − 18x + 4, where W is the amount of water in cubic feet and x is the number of hours the car wash is open. The owners of the car wash want to cut back their water usage during a drought and decide to close the car wash early two days a week. The amount of decrease in water used is modeled by D(x) = x3 + 2x2 + 15, where D is the amount of water in cubic feet and x is time in hours.

Write a function, C(x), to model the water used by the car wash on a shorter day.
C(x) = 2x3 + 2x2 − 18x − 11
C(x) = 3x3 + 2x2 − 18x + 11
C(x) = 3x3 + 2x2 − 18x − 11
C(x) = 2x3 + 2x2 − 18x + 11

Answers

Answer 1

Answer:

A C(x) =2x³+2x²-18x-11

Step-by-step explanation:

C(x) = W(x) - D(x)

plug W(x) and D(x) into equation

C(x) = 3x³+4x²-18x+4 - (x³+2x²+15)

add like terms now

C(x) =2x³+2x²-18x-11

Answer 2
W(x) is giving you the normal usage, D(x) is telling you by how much W(x) decreases. To find out what the actual usage is after the decrease we are going to have to subtract D(x) from W(x). I’m going to attach an image of how I did that, but basically your just subtracts the coefficients (number in front) where the exponents are the same. Also, don’t forget that since there is no x in D(x) we add in a +0X as a place holder.
I ended up with C(x)=2X^3+2X^2-18X-11 (option 1) Let me know if you have any questions.
PLLLLSSSS HELPP IM MARKING BRAINLIESTThe Water Usage At A Car Wash Is Modeled By The Equation W(x) =

Related Questions

How many stripes does each zebra have if there are 6 zebras at the zoo, 162 stripes in all, and all the zebras have the same number of stripes?

Answers

Answer:

27 stripes

Step-by-step explanation:

162/6=27

Since each zebra has the sam amount of stripes, you will divide the amount of stripes my the amount of zebras.

What do the solutions of a quadratic equation represent graphically? What is the maximum number of solution(s) given by solving a quadratic?

Answers

Answer:

The solutions of a quadratic equation on a graph is the point where the graph cuts across the x and y axes. The maximum number of solutions given by solving a quadratic equation is 2 solutions because the maximum power in a quadratic equation is power 2

Final answer:

The solutions of a quadratic equation represent the points where the graph, or parabola, crosses the x-axis. Those points are known as the roots of the equation. A quadratic equation can have up to two solutions.

Explanation:

In mathematics, the solutions of a quadratic equation graphically represent the points where the parabola (graph of the equation) crosses the x-axis. These points are commonly known as the roots or zeros of the quadratic equation. The maximum number of solutions a quadratic equation can have is two. This is due to the highest power in a quadratic equation (ax² + bx + c = 0) being '2'. However, it's also possible for it to have one or no solutions, depending on the values of a, b, and c, specifically their discriminant value (b² - 4ac).

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Sadie’s family orders a medium pizza with one topping, a large pizza with three toppings, two salads, and an order of breadsticks. What is the cost of the bill before tax or tip?

A. $40.25
B. $43.00
C. $44.00
D. $39.25

Answers

Answer:the answers is B

Step-by-step explanation:

A large company that must hire a new president prepares a final list of five candidates, all of whom are equally qualified. Two of these candidates are members of a minority group. To avoid bias in the selection of the candidate, the company decides to select the president by lottery. a. What is the probability one of the minority candidates is hired

Answers

Final answer:

The probability of one of the minority candidates being hired is 40%.

Explanation:

To find the probability that one of the minority candidates is hired, we need to determine the number of favorable outcomes (one of the minority candidates being selected) and divide it by the total number of possible outcomes (selecting any candidate from the final list of five).

Since there are two minority candidates and five candidates total, the probability of selecting one of the minority candidates is

P(one of the minority candidates being hired) = 2/5 = 0.4 = 40%

A rectangular tank with a square​ base, an open​ top, and a volume of 5324 ft cubed is to be constructed of sheet steel. Find the dimensions of the tank that has the minimum surface area.

Answers

Answer:

Step-by-step explanation:

I can't unless you give me the length and width or its impossible

The poll found that 38% of a random sample of 1012 American adults said they believe in ghosts. What is the lower bound for a 90% confidence interval for the percentage of all American adults who believe in ghosts?

Answers

Answer:

The lower bound for a 90% confidence interval for the percentage of all American adults who believe in ghosts is 0.3549

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which

z is the zscore that has a pvalue of [tex]1 - \frac{\alpha}{2}[/tex].

For this problem, we have that:

[tex]n = 1012, \pi = 0.38[/tex]

90% confidence level

So [tex]\alpha = 0.1[/tex], z is the value of Z that has a pvalue of [tex]1 - \frac{0.1}{2} = 0.95[/tex], so [tex]Z = 1.645[/tex].

The lower limit of this interval is:

[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.38 - 1.645\sqrt{\frac{0.38*0.62}{1012}} = 0.3549[/tex]

The lower bound for a 90% confidence interval for the percentage of all American adults who believe in ghosts is 0.3549

A train leaves Little Rock, Arkansas, and travels north at 60 kilometers per hour. Another train leaves at the same time & travels south at 65 kilometers per hour. How long will it take before they are 500 kilometers apart?

Answers

Answer:

3.704 Hours

Step-by-step explanation:

This problem can be solved by using concept of relative speed. relative speed is speed of one body in comparison of other.

If two bodies are moving in same direction their relative speed is calculated by taking difference of each other speed.

If two bodies are moving in opposite direction their relative speed is calculated by taking sum of each other speed.

In the problem stated two bodies are moving in north and south direction, hence they are moving in opposite direction, thus their speed can be taken sum of individual speed.

which is

(60+65) Km/Hr =  135 km/hour

Now given in question distance between two bodies is 500 KM

and relative speed = 135 km/hour

using formula of speed distance and time

Time = distance / speed  = 500/135 = 3.704 Hours

Therefore it will take 3.704 Hours for both of the trains to be 500 km apart.

The limit of a rational function at 5 equals the value of the rational function at 5 true or false

Answers

Girl you already know 5 is the equal

Which letter represents the maximum of the data set on the box plot?
A
B
C
D
E
30
35
40
45
50

Answers

50 is the Highest number

HELP ME WITH CALCULUS 1! I am stuck

Answers

answer

graph a

speeds up from (0,1) U (2,3) and slows down from (1,2)

if it marks (2,3) incorrectly, it may be from (2,∞) instead

graph b

speeds up from (1,2) U (3,4) and slows down from (0,1) U (2,3)

if it marks (3,4) incorrectly, it may be from (3,∞) instead

step-by-step explanation

looking at the velocity graphs, when the absolute value of velocity is increasing (moving away from the x axis), the particle must be speeding up. we say absolute value because while velocity has direction, speed only has magnitude, so we need to take the absolute value of velocity to get speed.

for graph a, we can see the velocity moving away from the x axis during the interval (0,1), moving towards the x axis during the interval (1,2) and then moving away again during the interval (2,3)

so it speeds up from (0,1) U (2,3) and slows down from (1,2)

if it marks (2,3) incorrectly, it may be from (2,∞) instead since this is at an endpoint

repeat for graph b where it moves toward the x axis from (0,1), moves away from (1,2), moves towards from (2,3), and moves away again from (3,4)

so it speeds up from (1,2) U (3,4) and slows down from (0,1) U (2,3)

if it marks (3,4) incorrectly, it may be from (2,∞) instead since this is at an endpoint

You are building a play area for the children. It will be 20 feet long. The total perimeter is 50 feet. What is the width of the play area?

Answers

Answer:

5

Step-by-step explanation:

20+20=40

50-40=10

10/2=5

To check our work we find the perimeter with our new width. 20+20+5+5=50

So we are right!!!

Teen obesity:
The 2013 National Youth Risk Behavior Survey (YRBS) reported that 13.7% of U.S. students in grades 9 through 12 who attend public and private schools were obese. [Source: Kann, L., Kinchen, S., Shanklin, S.L., Flint, K.H., Hawkins, J., Harris, W.A., et. al.(2013) YRBS 2013]
Suppose that 15% of a random sample of 300 U.S. public high school students were obese. Using the estimate from the 2013 YRBS, we calculate a standard error of 0.020. Since the data allows the use of the normal model, we can determine an approximate 95% confidence interval for the percentage of all U.S. public high school students who are obese.
Which interval is the approximate 95% confidence interval?

A) 0.097 to o.177
B) 0.117 to 0.157
C) 0.110 to 0.190
D) 0.013 to o.170

Answers

Answer:

95% confidence interval for the percentage of all U.S. public high school students who are obese is [0.110 , 0.190].

Step-by-step explanation:

We are given that 15% of a random sample of 300 U.S. public high school students were obese.

Firstly, the pivotal quantity for 95% confidence interval for the population proportion is given by;

                        P.Q. = [tex]\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex]  ~ N(0,1)

where, [tex]\hat p[/tex] = sample % of U.S. public high school students who were obese = 15%

           n = sample of U.S. public high school students = 300

           p = population percentage of all U.S. public high school students

Here for constructing 95% confidence interval we have used One-sample z proportion statistics.

So, 95% confidence interval for the population proportion, p is ;

P(-1.96 < N(0,1) < 1.96) = 0.95  {As the critical value of z at 2.5% level

                                             of significance are -1.96 & 1.96}  

P(-1.96 < [tex]\frac{\hat p-p}{\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < 1.96) = 0.95

P( [tex]-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < [tex]{\hat p-p}[/tex] < [tex]1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ) = 0.95

P( [tex]\hat p-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] < p < [tex]\hat p+1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] ) = 0.95

95% confidence interval for p = [[tex]\hat p-1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex] , [tex]\hat p+1.96 \times {\sqrt{\frac{\hat p(1-\hat p)}{n} } }[/tex]]

  = [ [tex]0.15-1.96 \times {\sqrt{\frac{0.15(1-0.15)}{300} } }[/tex] , [tex]0.15+1.96 \times {\sqrt{\frac{0.15(1-0.15)}{300} } }[/tex] ]

  = [0.110 , 0.190]

Therefore, 95% confidence interval for the percentage of all U.S. public high school students who are obese is [0.110 , 0.190].

The correct answer is option (c). The approximate 95% confidence interval is [tex]\[0.1108 \text{ to } 0.1892\][/tex]

To determine the approximate 95% confidence interval for the percentage of all U.S. public high school students who are obese, we'll use the standard error provided and the normal model.

The formula for the confidence interval is:

[tex]\[\hat{p} \pm Z \cdot \text{SE}\][/tex]

Now, we calculate the margin of error:

[tex]\[\text{Margin of Error} = Z \cdot \text{SE} = 1.96 \cdot 0.020 = 0.0392\][/tex]

Then, we determine the confidence interval by adding and subtracting the margin of error from the sample proportion:

[tex]\[\hat{p} - \text{Margin of Error} = 0.15 - 0.0392 = 0.1108\][/tex]

[tex]\[\hat{p} + \text{Margin of Error} = 0.15 + 0.0392 = 0.1892\][/tex]

Therefore, the approximate 95% confidence interval is:

[tex]\[0.1108 \text{ to } 0.1892\][/tex]

What is (f+g)(x)?
f(x)=-x
g(x)=3x+3
Write your answer as a polynomial or a rational function in simplest form.

Answers

Answer:

There u go

Step-by-step explanation:

(-x+3x+3)×x=2x^2+3x

2x^2+3x=x(2x+3)

Final answer:

The sum of the functions f(x) = -x and g(x) = 3x + 3 is computed as (f+g)(x) = f(x) + g(x), which simplifies to 2x + 3. This denotes a polynomial in simplest form.

Explanation:

The question is asking to compute the sum of two functions, f(x) = -x and g(x) = 3x+3 and to express it as a polynomial or a rational function in simplest form.

The sum of the two functions can be computed by adding together the outputs of the individual functions. In mathematical bricolage, this is known as function addition. The function sum (f+g)(x) can be calculated as f(x) + g(x).

If f(x) = -x and g(x) = 3x + 3, then (f+g)(x) can be calculated as follows:

(-x) + (3x + 3) = (-1x + 3x) + 3 = 2x + 3

So, (f+g)(x), in this case, is 2x + 3 which is a polynomial function in simplest form.

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From previous polls, it is believed that 66% of likely voters prefer the incumbent. A new poll of 500 likely voters will be conducted. In the new poll, if the proportion favoring the incumbent has not changed, what is the mean and standard deviation of the number preferring the incumbent?(a)mean = 330, standard deviation = 10.59(b)mean = 0.66, standard deviation = 10.59(c)mean = 330, standard deviation = 18.17

Answers

Answer:

The mean and standard deviation of the number preferring the incumbent is mean = 330, standard deviation = 10.59.

Step-by-step explanation:

We are given that From previous polls, it is believed that 66% of likely voters prefer the incumbent.

A new poll of 500 likely voters will be conducted. In the new poll the proportion favoring the incumbent has not changed.

Let p = probability of voters preferring the incumbent = 66%

n = number of voters polled = 500

So, the mean of the number preferring the incumbent is given by;

         Mean = [tex]n \times p[/tex] = [tex]500 \times 0.66[/tex]

                                = 330 voters

And, standard deviation of the number preferring the incumbent is given by;

          Variance =  [tex]n \times p\times (1-p)[/tex]  

                          =  [tex]500 \times 0.66 \times (1-0.66)[/tex]

                          =  112.2

So, Standard deviation =  [tex]\sqrt{Variance}[/tex]

                                       = [tex]\sqrt{112.2}[/tex]  = 10.59

Final answer:

Based on the binomial distribution and the probability of 66%, the mean number of likely voters favoring the incumbent is 330, and the standard deviation is approximately 18.17.

Explanation:

In this scenario, we are working with a binomial distribution where we have a fixed number of trials, each trial has two possible outcomes (in this case, favoring the incumbent or not), the probability of success is constant, and the trials are independent. Here, a success is a likely voter favoring the incumbent.

To find the mean of the number preferring the incumbent, we use the formula μ = np, where n is the number of trials (or voters), and p is the probability of a success. Thus, the mean is 500 voters times 66%, which gives us:

μ = 500 * 0.66 = 330.

The formula for the standard deviation (σ) of a binomial distribution is σ = √npq, where q is the probability of failure (1 - p). Therefore, standard deviation is:

σ = √(500 * 0.66 * (1 - 0.66)) = 18.17.

The correct answer is: mean = 330, standard deviation = 18.17

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please help im clueless

Answers

divide them together

To create a scale drawing of an Olympic standard swimming pool with a scale of 1 inch to 10 meters, the scaled dimensions would be approximately 2.5 inches for the width and 5 inches for the length.

To create a scale drawing of an Olympic standard swimming pool using a scale of 1 inch to 10 meters, we need to find the scaled dimensions. The actual dimensions of the pool are given as 50 meters in length and 25 meters in width.

Width:

Actual width: 25 meters

Scale factor: 10 meters per 1 inch

Scaled width = Actual width / Scale factor

Scaled width = 25 meters / 10 meters per 1 inch

Scaled width = 2.5 inches

Length:

Actual length: 50 meters

Scale factor: 10 meters per 1 inch

Scaled length = Actual length / Scale factor

Scaled length = 50 meters / 10 meters per 1 inch

Scaled length = 5 inches

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Suppose a simple random sample of size nequals36 is obtained from a population with mu equals 74 and sigma equals 6. ​(a) Describe the sampling distribution of x overbar. ​(b) What is Upper P (x overbar greater than 75.9 )​? ​(c) What is Upper P (x overbar less than or equals 71.95 )​? ​(d) What is Upper P (73 less than x overbar less than 75.75 )​?

Answers

Final answer:

The Central Limit Theorem explains the sampling distribution of the sample mean. We calculate probabilities using z-scores in the normal distribution for different scenarios. Understanding the concepts of sampling distributions and z-scores is essential for handling such questions in statistics.

Explanation:

The Central Limit Theorem states that for a large enough sample size, the sampling distribution of the sample mean will be approximately normally distributed, regardless of the population distribution.

(a) The mean of the sampling distribution of x  equals the population mean, which is 74, and the standard deviation of the sampling distribution σ/√n equals 6/√36 = 1.

(b) To find Upper P(x > 75.9), we standardize the value: z = (75.9 - 74) / 1 = 1.9. Consulting a z-table, we find P(z > 1.9) ≈ 0.0287.

(c) For Upper P(x< 71.95), we standardize: z = (71.95 - 74) / 1 = -2.05. From the z-table, P(z < -2.05) ≈ 0.0202.

(d) To find Upper P(73 < x < 75.75), we standardize both values, giving z(73) = (73 - 74) / 1 = -1 and z(75.75) = (75.75 - 74) / 1 = 1.75. Then, P(-1 < z < 1.75) = P(z < 1.75) - P(z < -1) ≈ 0.9599 - 0.1587 = 0.8012.

Mike heats some soup to 216 F. In order to eat the soup, he decides to let the soup cook in his kitchen. The following function represents the temperature of the soup, located in the kitchen with the air temperature of 73 F, after x minutes, where k is the constant rate at which the soup is cooking. T(x)= 73 +143 *e^(kx) If the temperature of the soup is 180 F after 8 minutes, then what is the approximate constant rate of cooling?

Answers

Answer:

-0.04

Step-by-step explanation:

The initial temperature of the soup is 216° F. After 8 minutes, the temperature of the soup is 180° F.

Set T(x) equal to 180, and set x equal to 8. Then, solve for r.

Therefore, the approximate constant rate of cooling is -0.04.

Answer:

Mark me brainliest please

Step-by-step explanation:

A manager is deciding whether or not to build a small facility. Demand is uncertain and can be either at a high or low level. If the manager chooses a small facility and demand is low, the payoff is $300. If the manager chooses a small facility and demand is high, the payoff is $100. On the other hand, if the manager chooses a large facility and demand is low, the payoff is -$200, but if demand is high, the payoff is $800.



(a) What would be the best decision based on the maximax criterion?



(b) What would be the best decision based on the maximin criterion?



(c) What would be the best decision based on the minimax regret?

Answers

Answer:

Check the explanation

Step-by-step explanation:

(a) Best decision based on maximax criterion= large facility

maximum in the two facilities is $300 and $800 of which $800 is the maximum, So larger facility satisfies maximax.

(b) Best decision based on maximin criterion= small facility

minimum in the two facilities is $100 and -$200 of which $100 is the maximum, So smaller facility satisfies maximin.

(c) Best decision based on minimax regret= large facility

maximum in the two facilities is $300 and $800 of which $300 is the minimum, So larger facility satisfies minimax regret.

Final answer:

Explanation of maximax, maximin, and minimax regret criteria for decision-making in uncertain scenarios.

Explanation:

Maximax criterion: This criterion involves selecting the decision with the maximum possible payoff under each possible outcome. In this case, the manager would choose the large facility due to the potential high payoff of $800 in case of high demand.

Maximin criterion: This criterion involves selecting the decision with the maximum possible payoff under the worst-case scenario. Here, the manager would choose the small facility to minimize the loss to -$200 in case of low demand.

Minimax regret: This criterion involves minimizing the maximum regret that could be incurred based on the wrong decision. The manager would need to calculate regrets for each decision and choose the one with the least possible regret

WILL GIVE BRAINLIEST ANSWER TO CORRECT ANSWER I need help with questions 2 part a,b,c and question 3 part a,b,c. Please, thank you !

Answers

Answer:

Q2

a) total sweets: 5 + 3 = 8

i) P(red) = 5/8

ii) P(yellow) = 3/8

b) for the second one:

4 red and 3 yellow left

i) P(red) = 4/7

ii) P(yellow) = 3/7

c) for the second one:

5 red and 2 yellow left

i) P(red) = 5/7

ii) P(yellow) = 2/7

Q3

a) total probability is 1

⅙ + ¼ + ⅓ + x = 1

x = 1 - (⅙ + ¼ + ⅓)

x = ¼

b) most likely is the color with highest probability, which is green

c) P(not red) = 1 - P(red)

= 1 - ⅙ = ⅚

Are the ratios 14:18 and 1:3 equivalent?

Answers

Answer:

PLEASE MARK AS BRAINLIEST PLZ

NOPE

Step-by-step explanation:

14:18 if you want to find the divisible number it is 2 now divide them both by 2it will be 7:9 and that's the most simple way

Answer:

No

Step-by-step explanation:

A way you can do it is to simplify the ratio, to make it smaller, but still equal to 14:18.

14:18 can be divided by 2, and turn to 7:9

This cannot be simplified so it is not equivalent.

Final answer

No

3. The Food Marketing Institute shows that 17% of households spend more than $100 per week on groceries. Assume the population proportion is p = .17 and a sample of 800 households will be selected from the population. a. Show the sampling distribution of p, the sample proportion of households spending more than $100 per week on groceries. b. What is the probability that the sample proportion will be within ±.02 of the population proportion? c. Answer part (b) for a sample of 1600 household

Answers

Answer:

A)sample proportion = 0.17,  the sampling distribution of p can be calculated/approximated with normal distribution of sample proportion = 0.17 and standard error/deviation = 0.013281

B) 0.869

C)0.9668

Step-by-step explanation:

A) p ( proportion of population that spends more than $100 per week) = 0.17

sample size (n)= 800

the sample proportion of p = 0.17

standard error of p = [tex]\sqrt{\frac{p(1-p)}{n} }[/tex] = 0.013281

the sampling distribution of p can be calculated/approximated with

normal distribution of sample proportion = 0.17 and standard error/deviation = 0.013281

B) probability that the sample proportion will be +-0.02 of the population proportion

= p (0.17 - 0.02 ≤ P ≤ 0.17 + 0.02 ) = p( 0.15 ≤ P ≤ 0.19)

z value corresponding to P

Z = [tex]\frac{P - p}{standard deviation}[/tex]

at P = 0.15

Z =  (0.15 - 0.17) / 0.013281 = = -1.51

at P = 0.19

z = ( 0.19 - 0.17) / 0.013281 = 1.51

therefore the required probability will be

p( -1.5 ≤ z ≤ 1.5 ) = p(z ≤ 1.51 ) - p(z ≤ -1.51 )

                           = 0.9345 - 0.0655 = 0.869

C) for a sample (n ) = 1600

standard deviation/ error = 0.009391 (applying the equation for calculating standard error as seen in part A above)

therefore the required probability after applying

z = [tex]\frac{P-p}{standard deviation}[/tex] at p = 0.15 and p = 0.19

p ( -2.13 ≤ z ≤ 2.13 ) = p( z ≤ 2.13 ) - p( z ≤ -2.13 )

                               = 0.9834 - 0.0166 = 0.9668

Final answer:

The sampling distribution of the sample proportion can be approximated by a normal distribution. The probability of the sample proportion being within a certain range can be calculated using z-scores.

Explanation:

a. The sampling distribution of p, the sample proportion of households spending more than $100 per week on groceries, can be approximated by a normal distribution with a mean of p and a standard deviation of √[(p(1-p))/n], where p is the population proportion and n is the sample size.

b. To find the probability that the sample proportion will be within ±0.02 of the population proportion, we calculate the z-scores for both values and find the area under the normal curve between those z-scores.

c. The probability of the sample proportion being within ±0.02 of the population proportion will remain the same for a sample of 1600 households, as long as the population proportion remains the same.

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An article reported that for a sample of 52 kitchens with gas cooking appliances monitored during a one-week period, the sample mean CO2 level (ppm) was 654.16, and the sample standard deviation was 164.55.


a) calculate and interpret a 95% confidence interval for true average CO2 level in the population of all homes from which the sample was selected .

b) Suppose the investigators had made a rough guess of 175 for the value of s before collecting data .What sanple size would be necessary to obtain an interval width of 50 ppm for confidence level of 95% ?

Answers

Answer:

a) [tex]654.16-2.01\frac{164.55}{\sqrt{52}}=608.29[/tex]    

[tex]654.16+2.01\frac{164.55}{\sqrt{52}}=700.03[/tex]    

And we can conclude that we are 95% confident that the true mean of Co2 level is between 608.29 and 700.03 ppm

b) [tex]n=(\frac{1.960(175)}{25})^2 =188.23 \approx 189[/tex]

Step-by-step explanation:

Part a

The confidence interval for the mean is given by the following formula:

[tex]\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex]   (1)

In order to calculate the critical value [tex]t_{\alpha/2}[/tex] we need to find first the degrees of freedom, given by:

[tex]df=n-1=52-1=51[/tex]

Since the Confidence is 0.95 or 95%, the value of [tex]\alpha=0.05[/tex] and [tex]\alpha/2 =0.025[/tex], and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,51)".And we see that [tex]t_{\alpha/2}=2.01[/tex]

Replacing we got:

[tex]654.16-2.01\frac{164.55}{\sqrt{52}}=608.29[/tex]    

[tex]654.16+2.01\frac{164.55}{\sqrt{52}}=700.03[/tex]    

And we can conclude that we are 95% confident that the true mean of Co2 level is between 608.29 and 700.03 ppm

Part b

The margin of error is given by :

[tex] ME=z_{\alpha/2}\frac{\sigma}{\sqrt{n}}[/tex]    (a)

The desired margin of error is ME =50/2=25 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

[tex]n=(\frac{z_{\alpha/2} s}{ME})^2[/tex]   (b)

The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025;0;1)", and we got [tex]z_{\alpha/2}=1.960[/tex], and we use an estimator of the population variance the value of 175 replacing into formula (b) we got:

[tex]n=(\frac{1.960(175)}{25})^2 =188.23 \approx 189[/tex]

This net can be folded to form a cube with a side length of 20 units

IM

What is the surface area of the cube in square units?

Answers

Answer:

The net, when folded into a cube, has a total surface area of 2,400 sq.units

Step-by-step explanation:

The length of all sides of a cube are the same.

Now, the surface area of a cube is the sum of the area of all of its faces.

Since the length of all sides are the same and we are told that the length of a side is 20 units, thus, the area of one face is;

A = 20 x 20 = 400 sq.units

So, one the area of a face is 400 sq.units.

Now, since all the faces are the same measurement, thus each face will have an area of 400 sq.units. Cubes have 6 faces, thus the total surface Area is;

Total = 400 x 6 = 2400 sq.units

The net, when folded into a cube, has a total surface area of 2,400 sq.units

Solve the equation.
3* = 27
x=L(Simplify your answer.)

Answers

Answer:

3³ = 27

This is because:

3x3x3 = 27

Your answer would be 3
3x3x3
\/ x 3
9 x 3
\ /
27

A certain type of thread is manufactured with a mean tensile strength of 78.3 kilograms and a standard deviation of 5.6 kilograms. How is the variance of the sample mean changed when the sample size is (a) increased from 64 to 196? (b) decreased from 784 to 49?

Answers

Answer:

(a) The variance decreases.

(b) The variance increases.

Step-by-step explanation:

According to the Central Limit Theorem if we have a population with mean μ and standard deviation σ and we take appropriately huge random samples (n ≥ 30) from the population with replacement, then the distribution of the sample mean will be approximately normally distributed.

Then, the mean of the sample mean is given by,

[tex]\mu_{\bar x}=\mu[/tex]

And the standard deviation of the sample mean is given by,

[tex]\sigma_{\bar x}=\frac{\sigma}{\sqrt{n}}[/tex]

The standard deviation of sample mean is inversely proportional to the sample size, n.

So, if n increases then the standard deviation will decrease and vice-versa.

(a)

The sample size is increased from 64 to 196.

As mentioned above, if the sample size is increased then the standard deviation will decrease.

So, on increasing the value of n from 64 to 196, the standard deviation of the sample mean will decrease.

The standard deviation of the sample mean for n = 64 is:

[tex]\sigma_{\bar x}=\frac{\sigma}{\sqrt{n}}=\frac{5.6}{\sqrt{64}}=0.7[/tex]

The standard deviation of the sample mean for n = 196 is:

[tex]\sigma_{\bar x}=\frac{\sigma}{\sqrt{n}}=\frac{5.6}{\sqrt{196}}=0.4[/tex]

The standard deviation of the sample mean decreased from 0.7 to 0.4 when n is increased from 64 to 196.

Hence, the variance also decreases.

(b)

If the sample size is decreased then the standard deviation will increase.

So, on decreasing the value of n from 784 to 49, the standard deviation of the sample mean will increase.

The standard deviation of the sample mean for n = 784 is:

[tex]\sigma_{\bar x}=\frac{\sigma}{\sqrt{n}}=\frac{5.6}{\sqrt{784}}=0.2[/tex]

The standard deviation of the sample mean for n = 49 is:

[tex]\sigma_{\bar x}=\frac{\sigma}{\sqrt{n}}=\frac{5.6}{\sqrt{49}}=0.8[/tex]

The standard deviation of the sample mean increased from 0.2 to 0.8 when n is decreased from 784 to 49.

Hence, the variance also increases.

Variance has decreased in first case and Variance has increased in second case.

Variation based problem:

What information do we have?

Mean tensile stength = 78.3 kilograms

Standard variance = 5.6 kilogram

Variance = sigma² / n

A.

Variance of sample mean with sample size 64 = 5.6² / 64

Variance of sample mean with sample size 64 = 0.49

Variance of sample mean with sample size 196 = 5.6² / 196

Variance of sample mean with sample size 196 = 0.16

Variance has decreased.

B.

Variance of sample mean with sample size 784 = 5.6² / 784

Variance of sample mean with sample size 784 = 0.04

Variance of sample mean with sample size 49 = 5.6² / 49

Variance of sample mean with sample size 49 = 0.64

Variance has increased.

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Suppose that the money demand function takes the form If output grows at rate and the nominal interest rate is constant, at what rate will the demand for real balances grow

Answers

Complete Question

Suppose that the money demand function takes the form

(M/P)^d = L(i,Y) = Y/(5i)

a. If output grows at rate and the nominal interest rate is constant, at what rate will the demand for real balances grow

b. What is the velocity of money in this economy

Answer:

a. See explanation below

b. Velocity = 5i

Step-by-step explanation:

a. Suppose that the nominal interest rate remains constant, the demand for real balances will grow at the same rate at which the output grows.

b.

Given that (M/P)^d = L(i,Y) = Y/(5i)

Money equation is written as;

Total Spending = MV

Where M = Amount of Money..

V = Velocity of Circulation

Total Spending = PY;

So, PY = MV --- Make V the subject of formula

PY/M = V --- Rearrange

V = PY/M ---- (1)

Also,

M/P = Y/5i --- Cross Multiply

M * 5i = P * Y --- Make 5i the subject of formula

5i = PY/M ---- (2)

Compare 1 and 2

5i = V = PY/M

So, 5i = V

V = 5i

Hence, Velocity = 5i

97% of £698.04 rounded to 2 decimal places

Answers

Rewrite the percent as a decimal by moving the decimal point 2 places to the left:

97% = 0.97

Now multiply:

698.04 x 0.97 = 677.0988

Round to 2 decimal places= 677.10

Final answer:

To find 97% of £698.04, you simply multiply £698.04 by 0.97. This gives you an answer of £677.30, rounded to 2 decimal places.

Explanation:

The question is asking for 97% of £698.04. To find this, you would need to multiply £698.04 by 0.97 (which is the decimal equivalent of 97%). Let's do this calculation:

£698.04 * 0.97 = £677.30

Here, the result (rounded to 2 decimal places) is £677.30. So, 97% of £698.04 is £677.30.

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Two circles lie in space. Which of the following can not occur if they were to intersect?
A. Three points
B. Two points
C. One point
D. Infinitely many points
E. None of the above

Answers

Answer:

  A.  Three points

Step-by-step explanation:

Tangent circles will intersect at the one point of tangency.

Circles that cross each other will intersect in two points.

Circles that are coincident will intersect in infinitely many points.

It is not possible for two circles to intersect in exactly 3 points.

examine the system of equations 4.2x + 8y=41.8 -4.2 + y= 19.4
use the linear combination method to solve the system of equations what is the value of x

Answers

Answer:

-3

Step-by-step explanation:

i know because i took the test

Answer:

-3 a)

Step-by-step explanation:

bc

What is 0.1 repeating. Convert to a FRACTION

Answers

Answer:

0.1111... = 0.1 = 1/9

Step-by-step explanation:

0.1111.. Is a repeating decimal which can be written as 0.1 and 1/9

It is important to know that the decimals which have only 1 digit repeating all come from the fractions which are ninths.

The fraction form of a number 0.11... is,

⇒ 1/9

We have to given that,

A number 0.1 repeating.

Now, We can find the fraction of number 0.111.. as,

Let us take,

x = 0.1111.....   .. (i)

Multiply by 10,

10x = 1.1111....  .. (ii)

Subtract (ii) from (i);

10x - x = 1.111.. - 0.1111....

9x = 1

x = 1/9

Hence, The fraction form of a number 0.11... is,

⇒ 1/9

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