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3 years ago

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Samples of size n = 4000 are randomly selected from a population of homeowners in Florida. The square footage of the home is rec

orded and the mean is found for each sample. What is the distribution of the sample mean?

2 answers:

mash [69]3 years ago

8 0

The answer is normal distribution.

Sampling distributions of means normally have normal distributions.

QveST [7]3 years ago

6 0

Answer:

Full Test Sampling Distributions Quiz Unit 8: Lesson 3 SCCA

Step-by-step explanation:

1. B. mean, variance, proportion

2. D. variance, mean, proportion

3. A. proportion

4. A. The sampling distribution of the variance requires repeating this process with the same sample several times. So this does not compare to the sampling distribution of the variance.

5. C. This is just one sample. The sampling distribution of the mean requires repeating this process with the same sample several times.

6. B. No, the sampling distribution of the proportion is the distribution of the proportions from all samples, not just one.

7. A. (question: you randomly survey 25 people at a time) Answer: not a normal distribution

8. A (question: samples of size n=20) Answer: normal distribution skewed to the right.

9. B. (question: sample of size n=4000) Answer: normal distribution.

10. C. (question: You roll a die 8 times) Answer: not a normal distribution.

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Let X1, X2, ... , Xn be a random sample from N(μ, σ2), where the mean θ = μ is such that −[infinity] < θ < [infinity] and

Sliva [168]

Answer:

$l'(\theta) = \frac{1}{\sigma^2} \sum_{i=1}^n (X_i -\theta)$

And then the maximum occurs when $l'(\theta) = 0$ , and that is only satisfied if and only if:

$\hat \theta = \bar X$

Step-by-step explanation:

For this case we have a random sample $X_1 ,X_2,...,X_n$ where $X_i \sim N(\mu=\theta, \sigma)$ where $\sigma$ is fixed. And we want to show that the maximum likehood estimator for $\theta = \bar X$ .

The first step is obtain the probability distribution function for the random variable X. For this case each $X_i , i=1,...n$ have the following density function:

$f(x_i | \theta,\sigma^2) = \frac{1}{\sqrt{2\pi}\sigma} exp^{-\frac{(x-\theta)^2}{2\sigma^2}} , -\infty \leq x \leq \infty$

The likehood function is given by:

$L(\theta) = \prod_{i=1}^n f(x_i)$

Assuming independence between the random sample, and replacing the density function we have this:

$L(\theta) = (\frac{1}{\sqrt{2\pi \sigma^2}})^n exp (-\frac{1}{2\sigma^2} \sum_{i=1}^n (X_i-\theta)^2)$

Taking the natural log on btoh sides we got:

$l(\theta) = -\frac{n}{2} ln(\sqrt{2\pi\sigma^2}) - \frac{1}{2\sigma^2} \sum_{i=1}^n (X_i -\theta)^2$

Now if we take the derivate respect $\theta$ we will see this:

$l'(\theta) = \frac{1}{\sigma^2} \sum_{i=1}^n (X_i -\theta)$

And then the maximum occurs when $l'(\theta) = 0$ , and that is only satisfied if and only if:

$\hat \theta = \bar X$

6 0

3 years ago

PLEASE HELP ME ITS SO URGENT!

stich3 [128]

Answer:

y=-8x

x=-3

Step-by-step explanation:

7 0

2 years ago

Jane made a poster that had a length of 1 2/3 feet and a width of 5/6 feet. What is the perimeter of her poster?

RoseWind [281]

Answer:

5 feet

Step-by-step explanation:

7 0

3 years ago

Can someone help me on 4 please

Kay [80]

To solve for x, we need to isolated and to do so, we would have to divide it by 1/6 since it's being multiplied by 1/6. To divide it, we have to do the reciprocal, which is getting any number and flipping it. So, we multiply both sides by 6 and we get 12 on one side and x on the other side.
So, x equals 12
I hope this helps
YOU'RE WELCOME :D

*brainliest*

7 0

2 years ago

Read 2 more answers

A chemist measures 8 grams of a substance that

Greeley [361]

Answer:

$y(t) =8 (b)^t$ Where b is the decay rate for this case. Using the condition given we have:

$4 = 8 b^6$

$\frac{1}{2}= b^6$

$b = (\frac{1}{2})^{1/6}$

And our model would be given by:

$y(t) = 8 (\frac{1}{2})^{t/6}$

And replacing the value of t=15 we got:

$y(15) = 8 (\frac{1}{2})^{15/6} = 1.414 grams$

Step-by-step explanation:

For this case since the half life is 6 hours we have the following condition:

$y(6) = \frac{1}{2}A_o$

Where $A_o=4$ is the initial amount

Our model for this case is given by this expression:

$y(t) =8 (b)^t$ Where b is the decay rate for this case. Using the condition given we have:

$4 = 8 b^6$

And solving for b we got:

$\frac{1}{2}= b^6$

And solving for b we got:

$b = (\frac{1}{2})^{1/6}$

And our model would be given by:

$y(t) = 8 (\frac{1}{2})^{t/6}$

And replacing the value of t=15 we got:

$y(15) = 8 (\frac{1}{2})^{15/6} = 1.414 grams$

5 0

2 years ago