Which inequality's graph will have a solid boundary line?

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

Can anyone help me? My teacher just recently taught me this today, be he never explained much. The question is in the photo

IceJOKER [234]

You've got five different problems in this photo ... four on top and the word problem on the bottom ... and they're all exactly the same thing: Taking two points and finding the slope of the line that goes through them.

In every case, the procedure is the same.
If the two points are (x₁ , y₁) and (x₂ , y₂) , then
the slope of the line that goes through them is

      Slope = (y₂ - y₁) / (x₂ - x₁) .

This is important, and you should memorize it.

#1). (8, 10) and (-7, 14)

   Slope = (14 - 10) / (-7 - 8) = 4 / -15

#2). (-3, 1) and (-17, 2)

   Slope = (2 - 1) / (-17 - -3) = (2 - 1) / (-17 + 3) = 1 / -14

#3). (-20, -4) and (-12, -10)

   Slope = [ -10 - (-4) ] / [ -12 - (-20) ]

=========================================

The word problem:

This question only gives you one point on the graph,
and then it wants to know what's the slope ?
What are you going to do for another point ?

A "proportional relationship" always passes through the origin,
so another point on the line is (0, 0) .

Now you have two points on THAT line too, and you can easily
find its slope.

4 0

3 years ago

In an algebra class last year, students who earned grades of A spent 4.7 hours more on homework per week than students who earne

Neko [114]

<span>A = 4.7 + C
where A represents the students who got A's, and C is the number of hours that the C-grade students spent on homework per week</span>

8 0

3 years ago

This is math please help !!!!!!!

aev [14]

Answer:

Hello I'lll solve this problem.

Step-by-step explanation:

So the answer is actually C. I did the work.

3 0

3 years ago

Urgent help needed...............

andreyandreev [35.5K]