When engaging in weight control (fitness/fat burning) types of exercise, a person is expected to attain about 60% of their maximum heart rate. For 20-year-olds, this rates is approximately 120 bpm. A simple random sample of 100 20-year-olds was taken, and the sample mean was found to be 107 bpm with a standard deviation of 45 bpm. Researchers wonder if this is evidence to conclude that the expected level is actually lower than 120 bpm. To determine this, we test the following hypothesis:

H0 : ? = 120, Ha : ? < 120

Reference: Ref 17-2

A 95% confidence interval for the population mean weight control heart rate, ?, of 20-year-olds is

Answers

Answer 1

Answer:

- There is enough evidence to support the claim that the heart rate level lower than 120 bpm  (P-value=0.002).

- The 95% confidence interval for the population mean weight control heart rate of 20-year-olds is (98.07, 115.93).

Step-by-step explanation:

This is a hypothesis test for the population mean.

The claim is that the heart rate level lower than 120 bpm

Then, the null and alternative hypothesis are:

[tex]H_0: \mu=120\\\\H_a:\mu< 120[/tex]

The significance level is 0.05.

The sample has a size n=100.

The sample mean is M=107.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=45.

The estimated standard error of the mean is computed using the formula:

[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{45}{\sqrt{100}}=4.5[/tex]

Then, we can calculate the t-statistic as:

[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{107-120}{4.5}=\dfrac{-13}{4.5}=-2.889[/tex]

The degrees of freedom for this sample size are:

[tex]df=n-1=100-1=99[/tex]

This test is a left-tailed test, with 99 degrees of freedom and t=-2.889, so the P-value for this test is calculated as (using a t-table):

[tex]P-value=P(t<-2.889)=0.002[/tex]

As the P-value (0.002) is smaller than the significance level (0.05), the effect is  significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the heart rate level lower than 120 bpm .

Confidence interval:

We have to calculate a 95% confidence interval for the mean.

The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.

The sample mean is M=107.

The sample size is N=100.

When σ is not known, s divided by the square root of N is used as an estimate of σM:

[tex]s_M=\dfrac{s}{\sqrt{N}}=\dfrac{45}{\sqrt{100}}=\dfrac{45}{10}=4.5[/tex]

The t-value for a 95% confidence interval is t=1.984.

The margin of error (MOE) can be calculated as:

[tex]MOE=t\cdot s_M=1.984 \cdot 4.5=8.929[/tex]

Then, the lower and upper bounds of the confidence interval are:

[tex]LL=M-t \cdot s_M = 107-8.929=98.07\\\\UL=M+t \cdot s_M = 107+8.929=115.93[/tex]

The 95% confidence interval for the population mean weight control heart rate of 20-year-olds is (98.07, 115.93).

Answer 2

Using the t-distribution, it is found that the 95% confidence interval for the population mean weight control heart rate is (98.07, 115.93). Since the entire interval is lower than 120 bpm, it is evidence to conclude that the expected level is actually lower than 120 bpm.

We are given the standard deviation for the sample, which is why the t-distribution is used to solve this question.

The information given is:

Sample mean of [tex]\overline{x} = 107[/tex].Sample standard deviation of [tex]s = 45[/tex].Sample size of [tex]n = 100[/tex].

The confidence interval is:

[tex]\overline{x} \pm t\frac{s}{\sqrt{n}}[/tex]

The critical value, using a t-distribution calculator, for a two-tailed 95% confidence interval, with 100 - 1 = 99 df, is t = 1.984.

Hence:

[tex]\overline{x} - t\frac{s}{\sqrt{n}} = 107 - 1.984\frac{45}{\sqrt{100}} = 98.07[/tex]

[tex]\overline{x} + t\frac{s}{\sqrt{n}} = 107 + 1.984\frac{45}{\sqrt{100}} = 115.93[/tex]

The 95% confidence interval for the population mean weight control heart rate is (98.07, 115.93). Since the entire interval is lower than 120 bpm, it is evidence to conclude that the expected level is actually lower than 120 bpm.

A similar problem is given at https://brainly.com/question/15180581


Related Questions

According to this site, if you know the coordinates of two points on a line, what form would you use to write the equation of the
line? Explain the process for writing the equation. (Site 1)

Answers

You would use the POINT SLOPE FORMULA and the Slope Formula

which is as follows ...

slope formula : [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

point slope formula:  [tex]y - y_{1} = m(x - x_{1} )[/tex]

What function is graphed below?
y = cot(x)-2
y=tan(x)-2
y = cot(x)+2
y=tan(x)+2

Answers

Answer:

d

Step-by-step explanation:

The function y = tan(x) + 2 is shown in the provided graph option fourth is correct.

What is trigonometry?

Trigonometry is a branch of mathematics that deals with the relationship between sides and angles of a right-angle triangle.

The missing figure is in the picture please refer to the picture.

As we have a trigonometric function.

In the picture, the graph of a tanx is shown but 2 units up.

Thus, the function y = tan(x) + 2 is shown in the provided graph option fourth is correct.

Learn more about trigonometry here:

brainly.com/question/26719838

#SPJ2

The number of cell phone accounts in a certain country has increased exponentially for the last decade. The number of cell phone accounts​ (in millions) in this country can be approximated by the following function. Estimate the number of cell phone accounts in 2003.
f(x)= 114.8e.125x (0
What was the approximate number of cell phone accounts in 2003?

Answers

Answer:

See Below

Step-by-step explanation:

The equation estimating the number of cellphones in the country is:

[tex]f(x)=114.8 e^{0.125x}[/tex]

Where x = 0 corresponds to year 2000

thus,

x = 1 is year 2001

x = 2 is year 2002

x = 3 is year 2003

and so on...

We want approx. number of cellphones in the country in 2003. This corresponds to x = 3. So substituting in the equation we get:

[tex]f(x)=114.8 e^{0.125x}\\f(3)=114.8 e^{0.125(3)}\\f(3)= 167.03[/tex]

So, approximately there were 167.03 million cellphones in the country in 2003

In March, April, and June it rained 2 inches. In February, May, and September it rained 1 inch In August and
October, it rained 3 inches. And in January it only rained 4 inches. Which line plot represents the data?
x
x
.
X
.
X
X
X
1
2
3
4
5
✓ Done
Intro

Answers

Answer:

d

Step-by-step explanation:

ILL GIVE BRAINLIEST please please help (only help if u know the right answer)

Answers

Okay, to find the answer,

All we need to do it multiply !

[tex]\frac{f}{-3.2}[/tex] = 0.01

f = (0.01) × (-3.2)

f = -.032

I hope I helped :) Just comment if you have any questions and remember to vote me "brainliest" if you like my answer !!!

What is the density of an object with a mass of 20 g and volume of 10 cm3?

Answers

Answer:

2 g/cm^3

Step-by-step explanation:

D=m/V

=20g/10cm^3

=2g/cm^3

Density calculation based on mass and volume of an object is  2 g/cm³.

The density of an object is calculated by dividing its mass by its volume. In this case, with a mass of 20 g and volume of 10 cm³, the density can be calculated as:

Density = Mass / Volume = 20 g / 10 cm³ = 2 g/cm³

How many black cherry trees have a height of 80 or more feet?
(Group of answer choices)
A) 7
B) 5
C) 10
D) 17

Answers

17 cherry trees have 80 or more feet

The answer is: D) 17

A nonlinear function with at least one term raised to the power of two is known as a a. logarithmic function. b. quadratic function. c. hyperbolic function. d. cubic function.

Answers

Answer:

The option b) quadratic function is correctA nonlinear function with at least one term raised to the power of two is known as a quadratic function

Step-by-step explanation:

A nonlinear function with at least one term raised to the power of two is known as a quadratic function

FOR :

A non-linear system of equations is a set of equations where one or more terms have a variable of power two or higher .

In Algebra, linear functions are polynomials with highest exponent equal to 1 or of the form y = c where c is constant. Non-linear functions are all other rest functions with exponent atleast 2.

Hence A nonlinear function with at least one term raised to the power of two is known as a quadratic function

Therefore the option b) quadratic function is correct

What is the surface area of a square pyramid with a slant height of 6cm and the length of one side of the square base is 5cm

Answers

Answer:

S = 85cm^2

Step-by-step explanation:

The surface area of a square pyramid is given by the following formula:

[tex]S=2hb+b^2[/tex]

where it has taken into account the sum of the area of a square and four triangles:

[tex]4(\frac{hb}{2})+b*b=2bh+b^2[/tex]

h: slant height = 6cm

b: base = 5cm

By replacing in the formula you obtain:

[tex]S=2(5cm)(6cm)+(5cm)^2=85cm^2[/tex]

hence, the surface area is 85cm^2

George works for a shipping company, loading packages into a truck. How much work does George do on a 2-kg package when he lifts it to a height of 1.8 m?

Answers

Answer:

Work done by george = 35.28J

Step-by-step explanation:

We are given;

Mass; m = 2 kg

Height;h = 1.8 m

Now, we want to find how much work does George do on a 2-kg package at the height of 1.8m.

This is a potential energy problem.

The formula for work done is therefore;

W = mgh

Where;

m is mass

g is acceleration due to gravity which has a constant value of 9.8 m/s²

h is height

Thus, plugging in relevant values;

W = 2 x 9.8 x 1.8

W = 35.28 J

Final answer:

The work done by George on the 2-kg package when he lifts it to a height of 1.8 meters is calculated using the equation W = mgh, which results in 35.28 joules.

Explanation:

The question How much work does George do on a 2-kg package when he lifts it to a height of 1.8 m? requires the calculation of the work done against the force of gravity. To find the work done, the equation W = mgh is used, where W is the work done in joules, m is the mass in kilograms, g is the acceleration due to gravity (9.8 m/s2), and h is the height in meters.

To solve for the work done in this case: W = (2 kg)(9.8 m/s2)(1.8 m).

When you calculate this, it gives you the work done by George as W = 35.28 J (joules).

A simple random sample of 5 months of sales data provided the following information: Month:12345 Units Sold:9480859492 (a)Develop a point estimate of the population mean number of units sold per month. x

Answers

Answer:

89 units

Step-by-step explanation:

-The population's mean point estimate is equivalent to the sample mean.

Given the 5 month units sold is 94,80,85,94 and 92

-Mean is the average of the units sold over the 5 month period:

[tex]\bar X=\frac{\sum {x_i}}{n}\\\\=\frac{94+80+85+84+92}{5}\\\\=89[/tex]

Hence, the point estimate for the population mean is 89 units

According to a study conducted by an​ organization, the proportion of Americans who were afraid to fly in 2006 was 0.10. A random sample of 1 comma 100 Americans results in 121 indicating that they are afraid to fly. Explain why this is not necessarily evidence that the proportion of Americans who are afraid to fly has increased.

Answers

Answer:

Event is not unusual(p>0.05).

Step-by-step explanation:

Given that :

[tex]p=0.10\\\\n=1100\\\\x=121[/tex]

#The sample proportion is calculated as:

[tex]\hat p=\frac{x}{n}\\\\=\frac{121}{1100}\\\\=0.1100[/tex]

#Mathematically, the z-value is the value decreased by the mean then divided  the standard deviation :

[tex]z=\frac{\hat p- p}{\sqrt{\frac{p(1-p)}{n}}}\\\\\\\\=\frac{0.11-0.10}{\sqrt{\frac{0.10(1-0.10)}{1100}}}\\\\\\=1.1055[/tex]

#We use the normal probability table to determine the corresponding probability;

[tex]P(X\geq 121)=P(Z>1.1055)\\\\=0.1314[/tex]

Hence, the probaility is more than 0.05, thus the event not unusual  and thus  this is not necessarily evidence that the proportion of Americans who are afraid to fly has increased.

A spinner has 8

​equal-sized sections. Two

of the sections are yellow
.
a. What is the probability that the spinner will land on yellow
​?
b. Use words to describe the probability.

Answers

Answer:

1/4

Step-by-step explanation:

The probability that the spinner will land on yellow is 2/8 because 2 is how many of the sections are yellow and 8 is how many sections there are in total. However, you need to simplify this to 1/4 and that is your answer

Final answer:

The probability that a spinner with 8 equal sections will land on yellow is 2 out of 8, which simplifies to 1/4 or a 25% chance.

Explanation:

The question asks about the probability of a spinner with 8 equal-sized sections landing on yellow, where 2 of the sections are yellow. To calculate the probability:

Count the number of favorable outcomes (the yellow sections): 2 sections.Count the total number of possible outcomes (all sections of the spinner): 8 sections.Divide the number of favorable outcomes by the total number of possible outcomes to get the probability.

a. The probability that the spinner will land on yellow is 2 out of 8, or 1/4.

b. In words, the probability can be described as having a one in four chance or a 25% chance of landing on yellow when the spinner is spun.

Simplify: 1/4(-12+4/3)

Answers

After simplifying The answer is -8/3

Solve the equation for x, and enter your answer below.
7 x -5= 65​

Answers

x=10

Step-by-step explanation:

7x - 5=65

+5 +5 so the 5's cancel so add 5 to 65

7x =70 because you add 5 to 65 to get 70

7x 7

7 x cancels out so you answer will be

x=10

Answer:

x = 10

Step-by-step explanation:

7 x -5  = 65

7 times what? (x) - 5 equals 65

Well we know that x has to be less than 65 and more than 7 and -5.

So 7 must be multiplied by numbers 8, and up.

7 * 8 -5  = 51, NOT 65.

7 * 9 -5  = 58, NOT 65.

7 * 10 -5  = Does equal 65.

Therefore, x is equivalent to 10.

Refer to speeds at which cars pass through a checkpoint on the highway. Assume the speeds are normally distributed with a population mean of 61 miles per hour and a population standard deviation of 4 miles per hour. Calculate the probability that the next car passing will be travelling more than 66 miles per hour.

Answers

Answer:

Probability that the next car passing will be travelling more than 66 miles per hour is 0.10565.

Step-by-step explanation:

We are given that the the speeds are normally distributed with a population mean of 61 miles per hour and a population standard deviation of 4 miles per hour.

Let X = speed of car

The z-score probability distribution for normal distribution is given by;

           Z = [tex]\frac{ X-\mu}{\sigma}} }[/tex]  ~ N(0,1)

where, [tex]\mu[/tex] = population mean speed = 61 miles per hour

            [tex]\sigma[/tex] = standard deviation = 4 miles per hour

The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X.

Now, Probability that the next car passing will be travelling more than 66 miles per hour is given by = P(X > 66 miles per hour)

        P(X > 66) = P( [tex]\frac{ X-\mu}{\sigma}} }[/tex] > [tex]\frac{ 66-61}{4}} }[/tex] ) = P(Z > 1.25) = 1 - P(Z [tex]\leq[/tex] 1.25)

                                                     = 1 - 0.89435 = 0.10565                       

So, in the z table the P(Z [tex]\leq[/tex] x) or P(Z < x) is given. So, the above probability is calculated by looking at the value of x = 1.25 in the z table which has an area of 0.89435.

Hence, the probability that the next car passing will be travelling more than 66 miles per hour is 0.10565.

Final answer:

The probability that the next car passing will be traveling more than 66 miles per hour, given a mean speed of 61 mph and standard deviation of 4 mph, is approximately 10.56%.

Explanation:

To calculate the probability that the next car passing will be traveling more than 66 miles per hour, given the speeds are normally distributed with a mean of 61 miles per hour and a standard deviation of 4 miles per hour, we use the Z-score formula.

The Z-score formula is: Z = (X - μ) / σ, where μ is the mean, σ is the standard deviation, and X is the value we're interested in.

Substitute the given values into the formula to find the Z-score for 66 miles per hour.

Z = (66 - 61) / 4 = 5 / 4 = 1.25.

Next, we look up the Z-score of 1.25 on the standard normal distribution table or use a calculator to find the area to the left of Z. The area to the left of Z=1.25 is approximately 0.8944. To find the probability of a car traveling more than 66 miles per hour, we subtract this value from 1.

Probability = 1 - 0.8944 = 0.1056.

Therefore, the probability that the next car passing will be traveling more than 66 miles per hour is approximately 10.56%.

A carousel has eight evenly spaced seats shaped like animals. During each ride, the carousel makes between 8 and 9 clockwise revolutions. At the end of one ride, the carousel stops so that the lion is in the position where the zebra was when the ride started. Through how many degrees did the carousel rotate on this ride

Answers

Answer:

2931 + 51.4n/7 degrees where n is the number of animal from the lion to the zebra in the clockwise direction.

Step-by-step explanation:

We don't have details on the positions of the lion and the zebra prior to revolution but suppose the zebra is n animal away from the lion where n could be in the range of 0 to 6 in the clockwise direction. If n = 0, the zebra is next to the lion in line, and if n = 6, the zebra is right behind the lion.

In angular term, since all 8 animals are evenly spaced, there are 7 space in between them, each of them would span an angle of 360/7 degrees

Then the angular distance between the zebra and the lion is (n+1)360/7 degrees

If the carousel makes between 8 and 9 revolutions then the total angular distance is 8*360 + (n+1)360/7 = 2931 + 51.4n/7 degrees

Answer:

-2970, -3320

Step-by-step explanation:

The carousel makes between 8 and 9 clockwise revolutions

the position of the lion rotated to that of the zebra is two steps

now,

1 revolution = 360 degrees accomplished in 8 steps

1 step = 360/8 = 45 deg

=> position of  lion rotated to zebra = 2 × 45 = 90 deg

if 1 revolution = 360 accomplished in 9 steps

then

1 step = 360/9 = 40 deg

=> position of  lion rotated to zebra = 2 × 40 = 80 deg

since the rotation is in clockwise direction, a negative sign is required

FOR 8 Revolutions

in total the carousel rotates

-[8(360) + 90] degrees

= -2970 degrees

FOR 9 revolution

in total the carousel rotates

-[9(360) + 80] degrees

= -3320 degrees

Find the theoretical probability of the event when rolling a standard number cube. P(6)

Answers

Final answer:

The theoretical probability of rolling a 6 on a standard number cube is 1/6 or approximately 0.1667.

Explanation:

The theoretical probability of rolling a 6 on a standard number cube is 1/6 or approximately 0.1667.

To find the probability, we divide the number of successful outcomes (rolling a 6) by the total number of possible outcomes (numbers 1 to 6), which is 6.

So the probability is 1/6 or 0.1667.

Since a standard number cube has equal chances of landing on any number from 1 to 6, each outcome has the same probability of occurring, which is 1/6.

Thus, the theoretical probability of the event when rolling a standard number cube is found to be  1/6 or approximately 0.1667.

Final answer:

The theoretical probability of rolling a six on a standard six-sided die is 1 in 6, or P(6) = 1/6.

Explanation:

The student has asked about finding the theoretical probability of rolling a six, P(6), with a standard six-sided die. In a fair six-sided die, the outcomes are equally likely, meaning the probabilities for each number 1 through 6 are the same. Given that there are six possible outcomes, the probability of rolling any one specific number, for example 6, is 1 out of the 6 total possible outcomes. Therefore, P(6) = 1/6. This probability reflects that, theoretically, if we were to roll the die many times, we'd expect to roll a 6 in approximately one-sixth of all the rolls.

Maximum height___feet

Answers

Answer:

you are not aloud to cheat on tests please don't do that sorry can't answer to a cheater

Step-by-step explanation:

If I sent out 200 letters and got 80 responses. If I want 20 more responses how many more letters do I have to send out

Answers

Answer:

Step-by-step explanation:

50

A mechanic finds that 30% of his customers own foreign cars, and that 40% own dogs. Assuming that these events are independent, what percent of the customers have neither a foreign car nor a dog

Answers

Answer:

42%

Step-by-step explanation:

Answer:

Since the events are independent, 30% of his customers have neither a foreign car nor a dog.

Step-by-step explanation:

Let the total number of his customers = 100.

Since the events are independent,

customers with foreign cars + customers that own dogs + customers that have neither a foreign car nor a dog = 100.

But,

Customers with foreign cars = 30% = 30

Customers that own dogs = 40% = 40

Customers with neither foreign car nor dog  = x%

So that,

     30 + 40 + x = 100

       70 + x = 100

      x = 100 - 70

      x = 30

Customers with neither foreign car nor dog  = 30.

Converting this value to percentage,

             =  [tex]\frac{30}{100}[/tex] × 100                      

             = 30%.

Therefore, 30% of his customers have neither a foreign car nor a dog.

The price of a movie ticket after a 16% increase is $8.99. What was the price before increase?

Answers

Answer:

The price before the increase was $7.75.

Step-by-step explanation:

This question can be solved using a rule of three.

The price of a movie ticket after a 16% increase is $8.99.

This means that the current price, of $8.99, is 100+16 = 116% = 1.16 of the original

x, the original price, is 100% = 1. So

8.99 - 1.16

x - 1

[tex]1.16x = 8.99[/tex]

[tex]x = \frac{8.99}{1.16}[/tex]

[tex]x = 7.75[/tex]

The price before the increase was $7.75

Answer:

$7.75

Step-by-step explanation:

When a number is increased by a certain percentage, it means that the product of the percentage and the number is added to the number. The result is the increase of the original number by the given percentage.

As such, if the original number is x and it is increased by 16%, to get $8.99, this may be expressed mathematically as

16% * x + x = 8.99

1.16x = 8.99

x = 8.99/1.16

= $7.75  

The price before the increase was $7.75

Determine the center of the following data set by finding
the median.
Test Scores
47,50,43, 42, 42, 38, 49, 47, 42, 50

Answers

Answer:

The median of this set is 45.

Step-by-step explanation:

The mean weekly earnings of a sample of 30 construction workers was $759, with a standard deviation of $73, and the mean weekly earnings of a sample of 28 manufacturing workers was $658, with a standard deviation of $65. Construct a 85% confidence interval for the difference between the mean weekly earnings for construction workers and the mean weekly earnings for manufacturing workers. Round to the second decimal place.

Answers

Answer:

[tex] (759-658) -1.46 \sqrt{\frac{73^2}{30} +\frac{65^2}{28}}= 74.54[/tex]

[tex] (759-658) +1.46 \sqrt{\frac{73^2}{30} +\frac{65^2}{28}}= 127.46[/tex]

And the confidence interval for the difference of the two means is given by (74.54, 127.46)

Step-by-step explanation:

Information given:

[tex]\bar X_1 = 759[/tex] the sample mean for construction workers

[tex] s_1 =73[/tex] the sample standard deviation for construction workers

[tex]n_1 =30[/tex] sample size of construction workers

[tex]\bar X_2 = 658[/tex] the sample mean for manufacturing workers

[tex] s_2 =65[/tex] the sample standard deviation for manufacturing workers

[tex]n_2 =28[/tex] sample size of construction workers

Confidence interval

The confidence interval for the difference of means are given by:

[tex] (\bar X_1 -\bar X_2) \pm t_{\alpha/2} \sqrt{\frac{s^2_1}{n_1} +\frac{s^2_2}{n_2}}[/tex]

We need to find the degrees of freedom given by:

[tex] df = n_1 +n_2 -2= 30+28-2=56[/tex]

The confidence is 0.85 and the significance level would be [tex]1-0.85=0.15[/tex] and [tex]\alpha/2 = 0.075[/tex]. We need to find a critical value in the t distribution who accumulates 0.075 of the area on each tail and we got:

[tex] t_{\alpha/2}= \pm 1.46[/tex]

And then we can replace and we got:

[tex] (759-658) -1.46 \sqrt{\frac{73^2}{30} +\frac{65^2}{28}}= 74.54[/tex]

[tex] (759-658) +1.46 \sqrt{\frac{73^2}{30} +\frac{65^2}{28}}= 127.46[/tex]

And the confidence interval for the difference of the two means is given by (74.54, 127.46)

Part (a): The 80% confidence interval for the earnings difference is $77.51 to $124.49.

Part (b): The interval suggests 80% confidence in the true earnings difference falling within $77.51 to $124.49.

Part (c): Since zero isn't in the interval, there's a significant pay difference between construction and manufacturing workers.

Part (a): Construct an 80% confidence interval for the difference between the mean weekly earnings

Step 1: Identify the given data

- Construction workers:

 - Mean [tex](\(\bar{X_1}\)) = \$759[/tex]

 - Standard deviation [tex](\(s_1\)) = \$73[/tex]

 - Sample size [tex](\(n_1\))[/tex] = 30

- Manufacturing workers:

 - Mean [tex](\(\bar{X_2}\)) = \$658[/tex]

 - Standard deviation [tex](\(s_2\)) = \$65[/tex]

 - Sample size [tex](\(n_2\)) = 28[/tex]

Step 2: Determine the formula for the confidence interval

We use the formula for the confidence interval of the difference between two independent means:

[tex]\[ (\bar{X_1} - \bar{X_2}) \pm t_{\alpha/2} \cdot \sqrt{\frac{s_1^2}{n_1} + \frac{s_2^2}{n_2}} \][/tex]

Step 3: Calculate the standard error (SE) of the difference

[tex]\[ SE = \sqrt{\frac{s_1^2}{n_1} + \frac{s_2^2}{n_2}} \][/tex]

[tex]\[ SE = \sqrt{\frac{73^2}{30} + \frac{65^2}{28}} \][/tex]

[tex]\[ SE = \sqrt{\frac{5329}{30} + \frac{4225}{28}} \][/tex]

[tex]\[ SE = \sqrt{177.63 + 150.89} \][/tex]

[tex]\[ SE = \sqrt{328.52} \approx 18.12 \][/tex]

Step 4: Determine the degrees of freedom (df) using the Welch-Satterthwaite equation

[tex]\[ df = \frac{\left(\frac{s_1^2}{n_1} + \frac{s_2^2}{n_2}\right)^2}{\frac{\left(\frac{s_1^2}{n_1}\right)^2}{n_1-1} + \frac{\left(\frac{s_2^2}{n_2}\right)^2}{n_2-1}} \][/tex]

[tex]\[ df \approx \frac{328.52^2}{\frac{(177.63)^2}{29} + \frac{(150.89)^2}{27}} \][/tex]

[tex]\[ df \approx \frac{107,922.4}{1090.15 + 843.48} \][/tex]

[tex]\[ df \approx \frac{107,922.4}{1933.63} \approx 55.83 \approx 56 \][/tex]

Step 5: Find the t-value for an 80% confidence interval

For df ≈ 56 and [tex]\(\alpha/2 = 0.10\),[/tex] the t-value [tex](\(t_{0.10}\))[/tex] is approximately 1.296.

Step 6: Construct the confidence interval

[tex]\[ (\bar{X_1} - \bar{X_2}) \pm t_{\alpha/2} \cdot SE \][/tex]

[tex]\[ (759 - 658) \pm 1.296 \cdot 18.12 \][/tex]

[tex]\[ 101 \pm 23.49 \][/tex]

[tex]\[ (77.51, 124.49) \][/tex]

So, the 80% confidence interval for the difference between the mean weekly earnings is [tex]\((77.51, 124.49)\).[/tex]

Part (b): Explanation of the Confidence Interval

The 80% confidence interval [tex]\((77.51, 124.49)\)[/tex] means that we are 80% confident that the true difference between the mean weekly earnings of construction workers and manufacturing workers lies between [tex]\$77.51[/tex] and [tex]\$124.49[/tex]. In other words, if we were to take many samples and compute the confidence interval for each, about 80% of those intervals would contain the true difference in mean earnings.

Part (c): Is there a significant difference in pay?

To determine if there is a significant difference in pay, we look at whether the confidence interval includes zero. Since the 80% confidence interval for the difference in mean earnings (\(77.51, 124.49\)) does not include zero, we can conclude that there is a statistically significant difference in pay between construction workers and manufacturing workers at the 80% confidence level.

Complete Question:

HELP! will give brainliest if given right answers

Answers

7.  tails, odd, 4

P(tails) = 1/2

P(odd) = 3/6 = 1/2

P(4) = 1/6

P(tails then odd then 4) = (1/2)×(1/2)×(1/6) = 1/24 ≈ 0.041666

Answer: 1/24, 4.2%

8.  tails, 6 or 1, 3

P(6 or 1) = 2/6 = 1/3

P(3) = 1/6

P( tails, 6 or 1, 3) = (1/2)(1/3)(1/6) = 1/36 ≈ 0.027777

Answer: 1/36, 2.8%

9.  heads, not 2, even

P(heads) = 1/2

P(not 2) = 5/6

P(even) = 1/2

P(heads, not 2, even) = (1/2)(5/6)(1/2) = 5/24 ≈ 0.208333

Answer: 5/24, 20.8%

Answer:

7. 1/24  = 4.2%

8. 1/36  = 2.8%

9. 1/6 = 16.67%

All percentages are rounded

What is the slope of the line that passes through the points (-8, -6) and (-18, 6)

Answers

Answer:

Step-by-step explanation:

-8, -6
-18,6 Iands aisndbdhs sgbnsfsnsisv

Answer the question bellow

Answers

Answer:

D

Step-by-step explanation:

All of the other functions are functions that are just multiplicative. When we substitute any x for A, B,or C, y/x will be the same. In D y/x will vary.

If $5958 is invested in an account at 5.9% annual interest compounded quarterly, how much will be in the account in 7 years if no money is withdrawn (Round your answer to the nearest hundredth)?

Answers

Answer:

Pretty sure in 7 years with no money withdrawn it would be $8,418.65

Step-by-step explanation:

because you would find out what 5.9% of $5958 which would be $351.522 you get that by multiplying [5958*5.9%=351.522]

Then multiply 351.522 by 7 and you get 2460.654 [351.522*7=2460.654]

Finally you add 2460.654 and 5958 and you get 8418.654 [5958+2460.522=8418.654]

Then you round down .654 and you get [8418.65]

(06.01)
A class has 21 girls and 12 boys. What is the probability that a boy's name is drawn at random? (5 points)

Answers

Answer:

In my opinion I think the answer is C.12/33

Step-by-step explanation:

this would be the answer because...

1. First, add up the amount of boys and girls

21 girls+ 12 boys= 33 total

2. Next, since its asking for the probability for a boys name to de drawn at random, your going to divide 12 by 33

12/33

Answer:

it is c i took test good luck

Step-by-step explanation:

sike i lied your a is mine lol

Determine the slope of the line which contains the following points.
(-3,5) and (2,-6)

Answers

Your slope would be -1. -6-2 divided by 5-(-3) is -8 over 8, simplifying to -1

Answer:

I like it when im high marks a lil by and he say he fly but he dono ha ta fly OoOoooOoOoOOoO

Step-by-step explanation:

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