A study was conducted to determine if the salaries of elementary school teachers from two neighboring districts were equal. A sample of 15 teachers from each district was randomly selected. Test the claim that the salaries from both districts are equal. Use significance 0.05 and assume that the data are distributed normally. n x¯ s District 1: 15 $28,900 $2,300 District 2: 15 $30,300 $2,100 3A. What is the appropriate set of hypotheses (H0, H1)?
• µ1 – µ2 = 0, µ1 – µ2 ≠ 0
• µ1 – µ2 ≠ 0, µ1 – µ2 = 0
• µ1 – µ2 = 0, µ1 – µ2 < 0
• µ1 – µ2 = 0, µ1 – µ2 > 0 3B.
What is the correct confidence interval?
• (–2475, –325)
• (–2100, –700)
• (–2975, 175)
• (–3125, 325) 3C.
Are the salaries of the teachers from the two districts different?
• Yes.
• No.
• Sometimes.
• Depends on distribution.

Answer:

92

Step-by-step explanation:

She is taking four tests. She wants to average a 95 on those tests. Therefore, she must score 95*4=380 total. She scored 97 and 91, or 188 total. Therefore, she must score 380-188 = 192 total on her next two tests. Her maximum score possible on the fourth test is 100. Therefore, the lowest score possible for the third test would be 192-100=92

The lowest possible score Isabella could have made on the third test

is 92 marks.

A numerical expression is a mathematical statement written in the form of numbers and unknown variables. We can form numerical expressions from statements.

Given, Isabella must take four 100-point tests in her math class and her goal is to achieve an average grade of 95 on the tests.

So, The total marks she needs to score in four games is (4×95).

= 380.

Now, She scores 97 and 91 in her first and second tests.

So, She needs to score

380 - (97 + 91)

= 380 - 188.

= 192 in her two tests.

Now, The highest marks she can score in the fourth test is 100.

Therefore, The lowest possible marks she can score is,

= 192 - 100.

= 92.

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Answer:

Step-by-step explanation:

Figuring it out rn

Answer:

  see below

Step-by-step explanation:

The definition of a parallelogram is that opposite sides of the quadrilateral are parallel. Felice already knows one pair of opposite sides is parallel. By showing the slope of RQ is the same as the slope of ST, she can show the other pair of opposite sides is parallel, hence the figure is a parallelogram.

__

The other answer choices are essentially nonsense.

Answer:

Top Right

Step-by-step explanation:

Answer:

- frequency of action potentials

The central nervous system determines the strength of a stimulus based on the frequency of action potentials. The intensity of the stimulus is interpreted not by the size, but by the frequency at which these potentials are produced.

The central nervous system determines the strength of a stimulus based on the frequency of action potentials. The central nervous system uses action potentials to transfer and process information. An action potential is a brief electrical charge that travels along an axon. The strength or intensity of the stimulus is interpreted not by the size of the action potentials, but by the frequency at which they are produced. For instance, a slightly warm temperature may produce action potentials at a lower frequency than a very hot temperature, which would produce action potentials at a high frequency. The central nervous system decodes this frequency to understand the intensity of the stimulus.

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The length of a curve [tex]C[/tex] given parametrically by [tex](x(t),y(t))[/tex] over some domain [tex]t\in[a,b][/tex] is

[tex]\displaystyle\int_C\mathrm ds=\int_a^b\sqrt{\left(\frac{\mathrm dx}{\mathrm dt}\right)^2+\left(\frac{\mathrm dy}{\mathrm dt}\right)^2}\,\mathrm dt[/tex]

In this case,

[tex]x(t)=\cos(\cos4t)\implies\dfrac{\mathrm dx}{\mathrm dt}=-\sin(\cos4t)(-\sin4t)(4)=4\sin4t\sin(\cos4t)[/tex]

[tex]y(t)=\sin(\cos4t)\implies\dfrac{\mathrm dy}{\mathrm dt}=\cos(\cos4t)(-\sin4t)(4)=-4\sin4t\cos(\cos4t)[/tex]

So we have

[tex]\displaystyle\left(\frac{\mathrm dx}{\mathrm dt}\right)^2+\left(\frac{\mathrm dy}{\mathrm dt}\right)^2=16\sin^24t\sin^2(\cos4t)+16\sin^24t\cos^2(\cos4t)=16\sin^24t[/tex]

and the arc length is

[tex]\displaystyle\int_0^1\sqrt{16\sin^24t}\,\mathrm dt=4\int_0^1|\sin4t|\,\mathrm dt[/tex]

We have

[tex]\sin(4t)=0\implies4t=n\pi\implies t=\dfrac{n\pi}4[/tex]

where [tex]n[/tex] is any integer; this tells us [tex]\sin(4t)\ge0[/tex] on the interval [tex]\left[0,\frac\pi4\right][/tex] and [tex]\sin(4t)<0[/tex] on [tex]\left[\frac\pi4,1\right][/tex]. So the arc length is

[tex]=\displaystyle4\left(\int_0^{\pi/4}\sin4t\,\mathrm dt-\int_{\pi/4}^1\sin4t\,\mathrm dt\right)[/tex]

[tex]=-\cos(4t)\bigg_0^{\pi/4}-\left(-\cos(4t)\bigg_{\pi/4}^1\right)[/tex]

[tex]=(\cos0-\cos\pi)+(\cos4-\cos\pi)=\boxed{3+\cos4}[/tex]

In this exercise we have to use the knowledge of the integral to calculate the length of the arc:

The length of a curve is given by  [tex]3+ cos( 4)[/tex]

The length of a curve  given parametrically by  [tex](x(t), y(t))[/tex] over some domain  is [tex]t \in [a, b][/tex]

[tex]\int\limits_C \, ds = \int\limits^a_b {\sqrt{(\frac{dx}{dt})^2 + (\frac{dy}{dt})^2 } } \, dt[/tex]

Now performing the derivatives with respect to X and Y, we find that:

[tex]x(t) = cos(cos4t) \rightarrow \frac{dx}{dt} = -sin(cos4t)(-sin4t)(4)= 4sin4tsin(cos4t)\\y(t) = sin(cos4t) \rightarrow \frac{dy}{dt} = cos(cos4t)(-sin4t)(4)=-4sin4tcos(cos4t)[/tex]

So we have:

[tex](\frac{dx}{dt} )^2+(\frac{dy}{dt} )^2= 16sin^24tsin^2(cos4t)+16sin^24tcos^2(cos4t)= 16sin^24t[/tex]

And the arc length is:

[tex]\int\limits^1_0 {\sqrt{16sin^24t} } \, dt= 4\int\limits^1_0 {sin4t} \, dt\\sin(4t)=0 \rightarrow 4t=n\pi \rightarrow t= \frac{n\pi }{4}[/tex]

where n  is any integer; this tells us  [tex]sin(4t)\geq 0[/tex] on the interval [tex][0,\pi/4][/tex] and  [tex]sin(4t)<0[/tex] on [tex][\pi/4, 1][/tex]. So the arc length is:

[tex]=4(\int\limits^{\pi/4}_0 {sin(4t)} \, dt - \int\limits^1_{\pi/4} {sin(4t)} \, dt)\\=(cos(0)-cos(\pi))+(cos(4)-cos(\pi))= 3+cos(4)[/tex]

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Answer:

Step-by-step explanation:

Answer:

 h /r  =  2.55

Step-by-step explanation:

Area of a can:

 Total area of the can = area of (top + bottom)  + lateral area

lateral area  2πrh    without waste

area of base (considering that you use 2r square)  is 4r²

area of bottom      ( for same reason )                           4r²

Then Total area  =  8r² + 2πrh

Now can volume is   1000 = πr²h        h = 1000/πr²

And  A(r)  =   8r² + 2πr(1000)/πr²

A(r)  =   8r² + 2000/r

Taking derivatives both sides

A´(r)   =  16 r    - 2000/r²

If A´(r)  =  0              16 r    - 2000/r²   = 0

(16r³  - 2000)/ r²  =  0        16r³  - 2000  =  0

r³  =  125      

r = 5 cm      and      h  = ( 1000)/ πr²      h  = 1000/ 3.14* 25

h = 12,74  cm

ratio   h /r  =  12.74/5         h /r  =  2.55

To find the ratio of h to r for the most economical can, we need to minimize the amount of aluminum used. The ratio is 0.

To find the ratio of h to r for the most economical can, we need to minimize the amount of aluminum used. The total amount of aluminum used is given by the equation A = 8r^2 + 2πrh. To minimize A, we can take the derivative of A with respect to h and set it equal to 0. Solving this equation will give us the value of h in terms of r, and we can then find the ratio of h to r.

Taking the derivative of A with respect to h, we get dA/dh = 2πr. Setting this equal to 0 and solving for h, we find that h = 0. To find the ratio of h to r, we divide both sides of the equation by r, giving us h/r = 0.

Therefore, the ratio of h to r for the most economical can is 0.

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Answer: 1.41

Step-by-step explanation:

Test statistic(z) for proportion is given by :-

[tex]z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}[/tex]

, where p=population proportion.

[tex]\hat{p}[/tex]= sample proportion

n= sample size.

As per given , we have

[tex]H_0:\mu=0.68\\\\ H_a: \mu\neq0.68[/tex]

n= 102

[tex]\hat{p}=0.745[/tex]

Then, the test statistic (z) for this hypothesis test will be :-

[tex]z=\dfrac{0.745-0.68}{\sqrt{\dfrac{0.68(1-0.68)}{102}}}\\\\=\dfrac{0.065}{\sqrt{\dfrac{0.2176}{102}}}\\\\=\dfrac{0.065}{\sqrt{0.0021333}}\\\\=\dfrac{0.065}{0.04618802}=1.40729132792\approx1.41[/tex]

[Rounded to the two decimal places]

Hence, the  test statistic (z) for this hypothesis test = 1.41

Answer: It takes 15.8 seconds to slide down a 2000 ft slope.

Step-by-step explanation:

Since we have given that

[tex]t=\sqrt{\dfrac{d}{16\sin\theta}}[/tex]

where, t is the time taken,

d is the length to slide down a slope

sin θ is the angle at which it inclined.

So, we have d = 2000 ft

θ = 30°

So, the time taken is given by

[tex]t=\sqrt{\dfrac{2000}{16\sin 30^\circ}}\\\\t=\sqrt{\dfrac{2000}{8}}\\\\t=\sqrt{250}\\\\t=15.81\ seconds[/tex]

Hence, it takes 15.8 seconds to slide down a 2000 ft slope.

The time it takes to slide down a 2000 ft slope inclined at 30° is 250 seconds, calculated using the equation t = d / (16 sin θ).

We're given the equation for calculating time of a sled sliding down a slope as t = d / (16 sin θ). Here, d is the length of the slope, and θ is the incline of the hill slope.

To calculate the time it takes to slide down a 2000 ft slope inclined at 30°, we substitute the respective values into the formula: t = 2000 / (16 sin 30). The sin value for 30° is 0.5, so the formula simplifies to t = 2000 / (16 * 0.5), which yields t = 2000 / 8. By performing that division, we see that t = 250 seconds. Therefore, it takes 250 seconds to slide down a 2000 ft slope inclined at 30°.

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We use the Z-score to determine the probability of selecting a single woman with a height less than 64.9 inches, and the concept of a sampling distribution (standard error) for a sample of 22 women. Generally, the larger the sample size, the closer the sample mean gets to the population mean, making it usually more probable to select one woman with a height of less than 64.9 inches than for a sample of 22 women.

This question is about probability and statistics, and specifically about the Normal Distribution and its applications. We know that the height of women aged 20-29 is normally distributed with a mean of 64.4 inches and a standard deviation of 2.3 inches.

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Calculate probabilities for selecting 1 woman and a sample of 22 women with heights less than 64.9 inches; Compare which selection is more likely.

Given:

Mean (μ) = 64.4 inches

Standard deviation (σ) = 2.3 inches

Calculate the z-score:

z = (x - μ) / σ

  = (64.9 - 64.4) / 2.3

  = 0.5 / 2.3

  = 0.2174

Now, we look up the probability corresponding to a z-score of 0.2174 in the standard normal table.

The probability for z = 0.2174 is approximately 0.5869.

So, the probability of randomly selecting 1 woman with a height less than 64.9 inches is approximately 0.5869.

Calculate standard error:

SE = σ / √n

    = 2.3 / √(22)

    ≈ 0.489

Find the z-score for the sample mean:

z = ([tex]^-_x[/tex] - μ) /  σ

 = (64.9 - 64.4) / 0.489

 = 0.5 / 0.489

 ≈ 1.021

Now, we look up the probability corresponding to a z-score of 1.021 in the standard normal table.

The probability for z = 1.021 is approximately 0.8451.

So, the probability of selecting a sample of 22 women with a mean height of less than 64.9 inches is approximately 0.8451.

→ Probability of randomly selecting 1 woman with a height less than 64.9 inches: 0.5869

→ Probability of selecting a sample of 22 women with a mean height less than 64.9 inches: 0.8451

Since 0.8451 is greater than 0.5869, it is more likely to select a sample of 22 women with a mean height of less than 64.9 inches.

Answer:

The proof is wrong. The part that says 'take an element b ∈ A such that (a, b) ∈ R' is assuming that such an element b exists, and that may not be the case.  We can give the 'theorem' validation by adding the hypothesis ' each element of A is related to any other element of A', otherwise the 'theorem' is false. An example for that is the following relation on the natural numbers:

'a R b if both numbers are even'

This relation if crearly symmetric and transitive, but it is not reflexive, an odd number does not relate with itself. In fact, odd numbers dont relate with any number.

Final answer:

The error in the given "proof" lies in the assumption that an element b ∈ A exists such that (a, b) ∈ R, which is not necessarily true for all a ∈ A. Symmetry and transitivity of a relation R do not inherently guarantee its reflexivity.

Explanation:

The error in the "proof" that a symmetric and transitive relation R on a set A is also reflexive lies in the initial assumption. The proof assumes the existence of an element b ∈ A such that (a, b) ∈ R for an arbitrary a ∈ A, but this is not guaranteed. Reflexivity requires that (a, a) ∈ R for all a ∈ A, independently of the existence of any such b. The proof fails because it assumes a specific relationship exists (between a and b) to demonstrate reflexivity, which is a general property that must hold without needing to reference any other elements.

The properties of reflexivity, symmetry, and transitivity define an equivalence relation. Symmetry and transitivity alone do not imply reflexivity. Therefore, the statement that a symmetric and transitive relation is reflexive is incorrect without additional assumptions about R.

Answer:

Part A: The population are the American adult citizens, excluding the ones from Alaska and Hawaii. The population is the people which the sample is trying to represent, as a hole.

The sample is a portion of this population, and in this case is represented by a randomly selected amount of people whose response to the interview has been selected.

Part B: The sample here has been selected in two steps. The first step is the one that we must pay attention to: the numbered list of one million responses from around the US (excluding Alaska and Hawaii). Because these responses were obtained by an online survey, the sample looks like a convenience sampling, as it depends on the availability and willingness from participants to take part of the study (is not compulsory for everyone, so not everyone is going to response, then there are people that is not going to be represented by). The second step is the random selection of a part of the previous responses. This last part will ensure that, the individuals that took part of the group that was interviewed, are well represented in the results.

Part C: As it was mentioned, there is a selection bias, because the information from the sample comes from a specific group of people that has certain features that may not represent all American adults citizens. For example, the opinion of  those people who do not use internet, will not be considered (and they may be a large number of persons). This situations weaken the conclusions obtained in the study, as they are not representative of the hole population.

Answer:

77.53

Step-by-step explanation:

Sample size (n) = 15

Sample mean (μ) = 75

Sample variance (V) = 25

Sample standard deviation (σ) = 5

For a 95% confidence interval, z-score = 1.960

The upper limit of the confidence interval is defined as:

[tex]UL=\mu+z\frac{\sigma}{\sqrt{n}}\\UL=75+1.960\frac{5}{\sqrt{15}} \\UL = 77.53[/tex]

Therefore, the upper limit of the 95% confidence interval proposed is 77.53.

The upper limit of a 95% confidence interval for the population mean is approximately 76.98.

The upper limit of a 95% confidence interval for the population mean can be calculated using the formula:

Upper Limit = Sample Mean + (Z-value)(Standard Error)

In this case, since the sample size is 15 and the sample variance is 25:

Standard Error = sqrt(sample variance/sample size)

Z-value can be obtained from the standard normal distribution table or calculator based on the desired confidence level. For a 95% confidence level, the Z-value is approximately 1.96.

Plugging in the values:

Upper Limit = 75 + (1.96)(sqrt(25/15))

Upper Limit ≈ 76.98

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Answer:

a) 2π

b) 0

Step-by-step explanation:

Recall that for a parametrized differentiable curve C = (x(t), y(t)) with the parameter t varying on some interval [a, b]

[tex]\large \int_{C}[P(x,y)dx+Q(x,y)dy]=\int_{a}^{b}[P(x(t),y(t))x'(t)+Q(x(t),y(t))y'(t)]dt[/tex]

Where P, Q are scalar functions

a)

C(t) = (x(t), y(t)) = (cos(t), sin(t)), 0 ≤ t ≤ 2π

P(x,y) = -y ==> P(x(t),y(t)) = -y(t) = -sin(t)

Q(x,y) = x ==> Q(x(t),y(t)) = x(t) = cos(t)

x'(t) = -sin(t)

y'(t) = cos(t)

[tex]\large \int_{C}[-ydx+xdy]=\int_{0}^{2\pi}[(-sin(t))(-sin(t))+cos(t)cos(t)]dt=\\\\\int_{0}^{2\pi}[sin^2(t)+cos^2(t)]dt=\int_{0}^{2\pi}dt=2\pi[/tex]

b)

C(t) = (x(t), y(t)) = (2cos(πt), 2sin(πt)), 2 ≤ t ≤ 4

P(x,y) = y ==> P(x(t),y(t)) = y(t) = 2sin(πt)

Q(x,y) = x ==> Q(x(t),y(t)) = x(t) = 2cos(πt)

x'(t) = -2πsin(πt)

y'(t) = 2πcos(πt)

[tex]\large \int_{C}[ydx+xdy]=\int_{2}^{4}[(2sin(\pi t))(-2\pi sin(\pi t))+2cos(\pi t)2\pi cos(\pi t)]dt=\\\\4\int_{2}^{4}[cos^2(\pi t)-sin^2(\pi t)]dt=4\int_{2}^{4}cos(2\pi t)dt=\\\\4\left[\frac{sin(2\pi t)}{2\pi}\right]_2^4=\frac{2}{\pi}(sin(8 \pi)-sin(4\pi))=0[/tex]

Answer:

The answer is: y = 2/3x - 3

Step-by-step explanation:

Given point: (3, -1)

Given equation: y = 2/3x - 5, which is in the form y = mx + b where m is the slope and b is the y intercept.

Parallel lines have the same slope. Use the point slope form of the equation with the point (3, -1) and substitute:

y - y1 = m(x - x1)

y - (-1) = 2/3(x - 3)

y + 1 = 2/3x - 6/3

y + 1 = 2/3x - 2

y = 2/3x - 3

Proof:

f(3) = 2/3(3) - 3

= 6/3 - 3

= 2 - 3

= -1, giving the point (3, -1)

Hope this helps! Have an Awesome Day!!  :-)

[tex]\vec F(x,y,z)=(x^2+y)\,\vec\imath+(y^2+x)\,\vec\jmath+ze^z\,\vec k[/tex]

We want to find [tex]f(x,y,z)[/tex] such that [tex]\nabla f=\vec F[/tex]. This means

[tex]\dfrac{\partial f}{\partial x}=x^2+y[/tex]

[tex]\dfrac{\partial f}{\partial y}=y^2+x[/tex]

[tex]\dfrac{\partial f}{\partial z}=ze^z[/tex]

Integrating both sides of the latter equation with respect to [tex]z[/tex] tells us

[tex]f(x,y,z)=e^z(z-1)+g(x,y)[/tex]

and differentiating with respect to [tex]x[/tex] gives

[tex]x^2+y=\dfrac{\partial g}{\partial x}[/tex]

Integrating both sides with respect to [tex]x[/tex] gives

[tex]g(x,y)=\dfrac{x^3}3+xy+h(y)[/tex]

Then

[tex]f(x,y,z)=e^z(z-1)+\dfrac{x^3}3+xy+h(y)[/tex]

and differentiating both sides with respect to [tex]y[/tex] gives

[tex]y^2+x=x+\dfrac{\mathrm dh}{\mathrm dy}\implies\dfrac{\mathrm dh}{\mathrm dy}=y^2\implies h(y)=\dfrac{y^3}3+C[/tex]

So the scalar potential function is

[tex]\boxed{f(x,y,z)=e^z(z-1)+\dfrac{x^3}3+xy+\dfrac{y^3}3+C}[/tex]

By the fundamental theorem of calculus, the work done by [tex]\vec F[/tex] along any path depends only on the endpoints of that path. In particular, the work done over the line segment (call it [tex]L[/tex]) in part (a) is

[tex]\displaystyle\int_L\vec F\cdot\mathrm d\vec r=f(4,0,4)-f(4,0,0)=\boxed{1+3e^4}[/tex]

and [tex]\vec F[/tex] does the same amount of work over both of the other paths.

In part (b), I don't know what is meant by "df/dt for F"...

In part (c), you're asked to find the work over the 2 parts (call them [tex]L_1[/tex] and [tex]L_2[/tex]) of the given path. Using the fundamental theorem makes this trivial:

[tex]\displaystyle\int_{L_1}\vec F\cdot\mathrm d\vec r=f(0,0,0)-f(4,0,0)=-\frac{64}3[/tex]

[tex]\displaystyle\int_{L_2}\vec F\cdot\mathrm d\vec r=f(4,0,4)-f(0,0,0)=\frac{67}3+3e^4[/tex]

Answer:

There is a 26.39% probability that the coin comes up heads and the die comes up less than 4 and the roulette wheel comes up with a number greater than 17.

Step-by-step explanation:

We have to find the probability of the three separate events, and then multiply them.

coin comes up heads

There is a [tex]\frac{1}{2}[/tex] probability that the coin comes up heads.

the die comes up less than 4

The are 15 sides on the die, from 0 to 14.

The values that satisfy us are 0,1,2,3.

So the probability is [tex]\frac{4}{15}[/tex].

the roulette wheel comes up with a number greater than 17

There roulette wheel can come from 1 to 36. There are 19 values greater than 17. So this probability is [tex]\frac{19}{36}[/tex]

What is the probability that the coin comes up heads and the die comes up less than 4 and the roulette wheel comes up with a number greater than 17 ?

[tex]P = \frac{1}{2}*\frac{4}{15}*\frac{19}{36} = 0.2639[/tex]

There is a 26.39% probability that the coin comes up heads and the die comes up less than 4 and the roulette wheel comes up with a number greater than 17.

The combined probability of the coin landing on heads, the die rolling less than 4, and the roulette wheel landing on a number greater than 17 is found by multiplying the individual probabilities of each event.

The question involves calculating the combined probability of independent events in a probability experiment: flipping a coin, rolling a 15-sided die, and spinning a roulette wheel. Each event's probability is calculated separately and then multiplied together to find the probability of all events occurring simultaneously.

The probability the coin comes up heads is 0.5, because a fair coin has two sides and the event has a theoretical probability of 1 in 2. When rolling a 15-sided die, the probability it comes up less than 4 (that is, obtaining a 1, 2, or 3) is 3 out of 15, as there are 3 favorable outcomes out of 15 possible outcomes. And for the roulette wheel, assuming it has numbers from 0 to 36, the probability of spinning a number greater than 17 is 19 out of 38, since there are 19 numbers from 18 to 36 (excluding 0 and 00 which might also be present).

To find the combined probability, you would multiply these probabilities together:

Combined Probability = Probability(Heads) * Probability(Die < 4) * Probability(Roulette > 17)
= 0.5 * (3/15) * (19/38)

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Answer:

You are expected to lose $0.05 (or win -$0.05)

Step-by-step explanation:

Since the roulette wheel has the numbers 1 through 36, 0, and 00, there are 38 possible outcomes.

In this bet, you are allowed to pick 3 out of the 38 numbers. Thus, your chances of winning (P(W)) and losing (P(L)) are:

[tex]P(W)=\frac{3}{38}\\P(L) = 1 - P(W)\\P(L) = \frac{35}{38}\\[/tex]

The expected value of the bet is given by the sum of the product of each outcome pay by its probability. Winning the bet means winning $11 while losing the bet means losing $1. The expected value is:

[tex]EV = (11*\frac{3}{38}) -(1*\frac{35}{38})\\EV = -\$0.0525[/tex]

Therefore, with a $1 bet, you are expected to lose roughly $0.05

Answer: The critical value is: insufficient.

Step-by-step explanation: Refer to Exhibit 9-2. The p-value is:

a. .0500  

b. .0228  

c. .0456  

d. .0250

In order to test the hypotheses H0: μ ≤ 100 and Ha: μ > 100 at an α level of significance, the null hypothesis will be rejected if the test statistic z is:

The practice of concluding "do not reject H0" is preferred over "accept H0" when we:

a. have an insufficient sample size.  

b. have not controlled for the Type II error.  

c. are testing the validity of a claim.  

d. are conducting a one-tailed test.

In hypothesis testing, the critical value is: insufficient

Answer:

False.

Step-by-step explanation:

Hello!

29.9% is the proportion of adults aged 20 and over that were obese in January - September 2014.

This percentage was obtained from a sample of 27 787 adults, it's not a parameter but an estimation of the population proportion obtained from this sample.

I hope it helps!

False, the 29.9% does not represent a parameter for the specific population of 27,787 adults surveyed in the National Health Interview Survey (NHIS).

The 29.9% figure representing U.S. adults aged 20 and over who were estimated to be obese based on the NHIS data is a statistic, not a parameter of the surveyed 27,787 adults, as it aims to generalize the obesity rate to the broader U.S. adult population.

Instead, this percentage is a statistic representing an estimate of the entire U.S. adult population aged 20 and over, based on the sample surveyed.

In statistics, a parameter refers to a numerical measure that describes a characteristic of a population, whereas a statistic is a numerical measure that describes a characteristic of a sample from the population.

Therefore, since the 29.9% figure estimated from the NHIS sample aims to generalize to the broader U.S. adult population, it is classified as a statistic, and not a parameter of the 27,787 adults directly surveyed.

Answer:

21, 144, 12

Step-by-step explanation:

Given that a sample of 30 distance scores measured in yards has a mean of 7, a variance of 16, and a standard deviation of 4.

Let X be the distance in yard.

i.e. each entry of x is multiplied by 3.

New mean variance std devition would be

E(3x) = [tex]3E(x) = 21[/tex]

Var (3x) = [tex]3^2 Var(x) = 9(16) =144[/tex]

Std dev (3x) = [tex]\sqrt{144 } =12[/tex]

Thus we find mean and std devition get multiplied by 3, variance is multiplied by 9

The new mean after converting the distances from yards to feet is 21, the median remains unchanged at 7, the new variance is 144, and the new standard deviation is 12.

To find the new mean, we multiply the original mean by the conversion factor. Since there are 3 feet in a yard, we have:

New Mean = Original Mean × Conversion Factor

 = 7 yards × 3 feet/yard

 = 21 feet

The median is a measure of central tendency that represents the middle value of a data set. When each data point is multiplied by a constant factor, the median is also multiplied by that factor. However, since the median is the middle value of an ordered list of data, and we are not changing the order or adding or removing any data points, the median in terms of yards and feet is the same numerical value, even though the units are different:

 New Median = [tex]Original Median Ã[/tex]— Conversion Factor

 = 7 yards (since the median is the same numerical value)

For the variance, when each data point is multiplied by a constant, the variance is multiplied by the square of that constant:

New Variance = [tex]Original Variance × (Conversion Factor)^2[/tex]

 = [tex]16 yards^2 × (3 feet/yard)^2[/tex]

 = [tex]16 yards^2 × 9 (feet^2/yard^2)[/tex]

 = [tex]144 feet^2[/tex]

Finally, the standard deviation is the square root of the variance, so to find the new standard deviation, we take the square root of the new variance:

New Standard Deviation = [tex]√New Variance[/tex]

 = [tex]√144 feet^2[/tex]

 = 12 feet

Answer:

50%

Step-by-step explanation:

68-95-99.7 rule

68% of all values lie within the 1 standard deviation from mean [tex](\mu-\sigma,\mu+\sigma)[/tex]

95% of all values lie within the 1 standard deviation from mean  [tex](\mu-1\sigma,\mu+1\sigma)[/tex]

99.7% of all values lie within the 1 standard deviation from mean  [tex](\mu-3\sigma,\mu+3\sigma)[/tex]

The distribution of the number of daily requests is bell-shaped and has a mean of 55 and a standard deviation of 4.

[tex]\mu = 55\\\sigma = 4[/tex]

68% of all values lie within the 1 standard deviation from mean [tex](\mu-\sigma,\mu+\sigma)[/tex] = [tex](55-4,55+4)[/tex]= [tex](51,59)[/tex]

95% of all values lie within the 2 standard deviation from mean  [tex](\mu-1\sigma,\mu+1\sigma)[/tex]= [tex](55-2(4),55+2(4))[/tex]= [tex](47,63)[/tex]

99.7% of all values lie within the 3 standard deviation from mean  [tex](\mu-3\sigma,\mu+3\sigma)[/tex]= [tex](55-3(4),55+3(4))[/tex]= [tex](43,67)[/tex]

Refer the attached figure

P(43<x<55)=2.5%+13.5%+34%=50%

Hence The approximate percentage of light bulb replacement requests numbering between 43 and 55 is 50%

Answer:

  x = 55°

Step-by-step explanation:

The sum of the angles in a triangle is 180°, so you have ...

  x + 50° +75° = 180°

  x = 55° . . . . . . . . . . . . subtract 125°

Answer:

Which is the output of the formula =AND(12>6;6>3;3>9)?

A.

TRUE

B.

FALSE

C.

12

D.

9

Step-by-step explanation:

Answer:

A correlation coefficient close to zero

Step-by-step explanation:

This makes linear regression unreasonable because the correlation coefficient shows how related the data points are, -1 and 1 being very strong and 0 being uncorrelated. So the line of best fit would not make sense because the data points are random in relation to one another.

Step-by-step explanation:

Answer:

C. convenience sample

Step-by-step explanation:

Convenience sampling is a type of non-probability sampling or non-random sampling which is any sampling method where some elements of the population have no chance of selection. The selection is left at the judgment of the interviewer or investigator and this non-randomness in the statistical sense implies that the interviewer or investigator do not fulfill some of the basic requirements or assumptions of the common standard methods for testing hypothesis and drawing inferences from the sample data to the target population

Answer:

[tex]H_{0}: \mu \leq 63500\\H_A: \mu > 63500[/tex]

Step-by-step explanation:

We are given the following in the question:

The owner of a football team claims that the average attendance at games is over 63,500.

He wants to justify that the team needs to be moved to a larger stadium outside the city.

If the attendance is larger than 63,500 the team would be moved to a larger stadium and if it is less than or equal to 63,500 that it would not.

Thus, the null and alternate hypothesis will be designed as:

[tex]H_{0}: \mu \leq 63500\\H_A: \mu > 63500[/tex]

The null hypothesis says that the average attenders is equal to or less than 63,500 and alternate supports the claim that the attenders average is greater than 63,500.

Answer:

The 98% confidence interval would be given (0.616;0.686).  

We are confident at 98% that the true proportion of people that they were planning to pursue a graduate degree is between (0.616;0.686).

Step-by-step explanation:

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".  

The margin of error is the range of values below and above the sample statistic in a confidence interval.  

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".  

Description in words of the parameter p

[tex]p[/tex] represent the real population proportion of people that they were planning to pursue a graduate degree

[tex]\hat p[/tex] represent the estimated proportion of people that they were planning to pursue a graduate degree

n=1010 is the sample size required  

[tex]z_{\alpha/2}[/tex] represent the critical value for the margin of error  

The population proportion have the following distribution  

[tex]p \sim N(p,\sqrt{\frac{p(1-p)}{n}})[/tex]

Numerical estimate for p

In order to estimate a proportion we use this formula:

[tex]\hat p =\frac{X}{n}[/tex] where X represent the number of people with a characteristic and n the total sample size selected.

[tex]\hat p=\frac{658}{1010}=0.651[/tex] represent the estimated proportion of people that they were planning to pursue a graduate degree

Confidence interval

The confidence interval for a proportion is given by this formula  

[tex]\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}[/tex]  

For the 98% confidence interval the value of [tex]\alpha=1-0.98=0.02[/tex] and [tex]\alpha/2=0.01[/tex], with that value we can find the quantile required for the interval in the normal standard distribution.  

[tex]z_{\alpha/2}=2.33[/tex]  

And replacing into the confidence interval formula we got:  

[tex]0.651 - 2.33 \sqrt{\frac{0.651(1-0.651)}{1010}}=0.616[/tex]  

[tex]0.651 + 2.33 \sqrt{\frac{0.651(1-0.651)}{1010}}=0.686[/tex]  

And the 98% confidence interval would be given (0.616;0.686).  

We are confident at 98% that the true proportion of people that they were planning to pursue a graduate degree is between (0.616;0.686).  

Answer:

Step-by-step explanation:

Answer:

The sum of squares due to regression(SSR)=928.02

Step-by-step explanation:

We are given that

Dependent variable=y

Independent variable=x

[tex]\sum x=90[/tex]

[tex]\sum(y-\bar y)(x-\bar x)=466[/tex]

[tex]\sum y=170[/tex]

[tex]\sum(x-\bar x)^2=234[/tex]

n=10

[tex]\sum(y-\bar y)^2=1434[/tex]

SSE=505.98

We have to find the sum of squares due to regression.

It means we have to find SSR.

SST=[tex]\sum(y-\bar y)^2=1434[/tex]

[tex]SSR=SST-SSE=1434-505.98=928.02[/tex]

Hence, the sum of squares due to regression(SSR)=928.02