What is the equation of a line with a slope of -2 and passes through the point 3,5¿

Can someone help with 6

olga nikolaevna [1]

A. there are 20 boys and 30 girls.

B.

68.7 out of 100 Boys

Girls im not sure, maybe someone else can answer that sorry

Hope I'm right and this helps sorry i didn't get girls.

8 0

3 years ago

An SRS of 350 high school seniors gained an average of x¯=21 points in their second attempt at the SAT Mathematics exam. Assume

Lynna [10]

Answer:

a) $21-2.58\frac{52}{\sqrt{350}}=13.83$

$21+2.58\frac{52}{\sqrt{350}}=28.17$

So on this case the 99% confidence interval would be given by (13.83;28.17)

b) $ME=2.58\frac{52}{\sqrt{350}}=7.17$

c) $ME=2.58\frac{52}{\sqrt{100}}=13.42$

d) D. Decreasing the sample size increases the margin of error, provided the confidence level and population standard deviation remain the same.

Step-by-step explanation:

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".

Part a

$\bar X=21$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=52$ represent the population standard deviation

n=350 represent the sample size

99% confidence interval

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

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

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

Now we have everything in order to replace into formula (1):

$21-2.58\frac{52}{\sqrt{350}}=13.83$

$21+2.58\frac{52}{\sqrt{350}}=28.17$

So on this case the 99% confidence interval would be given by (13.83;28.17)

Part b

The margin of error is given by:

$ME=2.58\frac{52}{\sqrt{350}}=7.17$

Part c

The margin of error is given by:

$ME=2.58\frac{52}{\sqrt{100}}=13.42$

Part d

As we can see when we reduce the sample size we increase the margin of error so the best option for this case is:

D. Decreasing the sample size increases the margin of error, provided the confidence level and population standard deviation remain the same.

6 0

3 years ago

Which real-world scenario can be described by the algebraic expression StartFraction p over 8 EndFraction?

Basile [38]

Answer:

the answer is D

Step-by-step explanation:

I just took a test

8 0

3 years ago

Read 2 more answers

HURRY NEED HELP NOW 42 POINTS NEED 1 PARAGRAPH FOR EACH QUESTION there are 2 photos I put up and that where the questions are.

Shtirlitz [24]

1. All you have to do to find the area of the figure. IS first find the area of the rectangle. This is easy because all you have to do is base times height.

22 x 17 = 374

Now to find the area of the triangle all you have to do is do base times height like a rectangle, but then divide it by 2 afterwords.
19 x 12 = 228 ÷ 2 = 114.

Now add the two area's together:

374 + 114 = 488.

Just do the same with the one below, I've altered the pic a bit to make it easier.

4 0

3 years ago

Suppose that the pages per book in a library are normally distributed with an unknown mean and standard deviation. The book leng

Elanso [62]

Answer:

A t-score of 2.0244 should be used to find the 99% confidence interval for the population mean

Step-by-step explanation:

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 39 - 1 = 38

Now, we have to find a value of T, which is found looking at the t table, with 38 degrees of freedom(y-axis) and a confidence level of 0.99( $t_{99}$ ). So we have T = 2.0244.

A t-score of 2.0244 should be used to find the 99% confidence interval for the population mean

6 0

3 years ago