Yeah I know pretty easy I’m just lost so can anyone help put

A doctor wants to estimate the mean HDL cholesterol of all 20- to 29-year-old females. The number of subjects needed to estima

Ludmilka [50]

Answer:

$n=(\frac{1.64(14.7)}{3})^2 =64.57 \approx 65$

So the answer for this case would be n=65 rounded up to the nearest integer

And the sample size would decrease by 160-65=95 subjects

Step-by-step explanation:

1) Previous concepts

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".

$\bar X$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

s represent the sample standard deviation

n represent the sample size

ME represent the margin of error

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

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

2) Solution to the problem

Since the new Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Assuming that the deviation is known we can express the margin of error is given by this formula:

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

And on this case we have that ME =\pm 3 and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=(\frac{z_{\alpha/2} \sigma}{ME})^2$ (b)

Replacing into formula (b) we got:

$n=(\frac{1.64(14.7)}{3})^2 =64.57 \approx 65$

So the answer for this case would be n=65 rounded up to the nearest integer

And the sample size would decrease by 160-65=95 subjects

8 0

3 years ago

One-fifth the sum of one-half and one-third. WRITE IN A EXPRESSION FORM

vladimir2022 [97]

Answer:

1/6

Step-by-step explanation:

1/2 + 1/3 = 5/6

1/5 of 5/6 = 5/30

5/30 can be simplified as 1/6.

8 0

3 years ago

Short Response<br> 6. Are the triangles at the right simílar? Explain.

Taya2010 [7]

Answer:

Yes they are similar because they are both right angles but the one on the right is bigger than the one on the left.

Step-by-step explanation:

5 0

3 years ago

Ronald is calculating the time required to fill the swimming pool at school. He found that it takes 8 minutes to fill the swimmi

tester [92]

Answer:

<u>The rate the swimming pool is filled is 9 gallons of water per minute</u>

Step-by-step explanation:

Let's review the information provided by Ronald to us to help him to find the answer to the question:

Time it takes to fill the swimming pool = 8 minutes

Amount of water the swimming pool can hold = 72 gallons

2. At what rate does the swimming pool fill, in gallons per minute?

Rate the swimming pool is filled = Amount of water the swimming pool can hold /Time it takes to fill the swimming pool

Replacing with the real values, we have:

Rate the swimming pool is filled = 72/8 = 9 gallons of water per minute

4 0

3 years ago

The cost of Spectrum Internet is $60 per month plus a one time $35 installation fee. How much would it cost to have internet for

Murljashka [212]

Answer:

$755

Step-by-step explanation:

You can use the formula c = 60m + 35 for this. c is the cost and m is the number of months. Since a year is 12 months, 60m = 60*12 = 720. Then add the one time fee of $35. 720 + 35 = 755.

4 0

3 years ago