Wht is the volume for both 7 and 8 Also rounded to the nearest tenth if ecessary

The points (2, r) and (5, -9) lie on a line with slope – 2. Find the missing coordinate r.

Veseljchak [2.6K]

Answer:

-3

Step-by-step explanation:

5-2 is three

3 times -2 is -6

-9-(-6) is -3

(2,-3)

3 0

3 years ago

A researcher is interested in finding a 95% confidence interval for the mean number minutes students are concentrating on their

Sever21 [200]

Answer:

A. Normal

B. Between 40.08 minutes and 43.92 minutes.

C. About 95 percent of these confidence intervals will contain the true population mean number of minutes of concentration and about 5 percent will not contain the true population mean number of minutes of concentration.

Step-by-step explanation:

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean $\mu = p$ and standard deviation $s = \sqrt{\frac{p(1-p)}{n}}$

x% confidence interval:

A confidence interval is built from a sample, has bounds a and b, and has a confidence level of x%. It means that we are x% confident that the population mean is between a and b.

Question A:

By the Central Limit Theorem, a normal distribution.

Question B:

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.025 = 0.975$ , so Z = 1.96.

Now, find the margin of error M as such

$M = z\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

$M = 1.96\frac{12}{\sqrt{150}} = 1.92$

The lower end of the interval is the sample mean subtracted by M. So it is 42 - 1.92 = 40.08 minutes

The upper end of the interval is the sample mean added to M. So it is 42 + 1.92 = 43.92 minutes

Between 40.08 minutes and 43.92 minutes.

Question C:

x% confidence interval -> x% will contain the true population mean, (100-x)% wont.

So, 95% confidence interval:

About 95 percent of these confidence intervals will contain the true population mean number of minutes of concentration and about 5 percent will not contain the true population mean number of minutes of concentration.

3 0

3 years ago

The Slope a line that goes through the points (r, 6 ) and (4,2 is 4 find r

olya-2409 [2.1K]

R= 5
(2-6). -4
—— = ——-
(4-r). (This has to be -1 for the answer to be 4)
4-5=-1
So r=5

4 0

3 years ago

Which is the correct answer for this?

alukav5142 [94]

Answer:

a

Step-by-step explanation:

i took the class

8 0

3 years ago

Read 2 more answers

Find the z-scores that delineate the middle 96% of all values from the others. enter your answers to 2 or 3 decimal places. from

scZoUnD [109]

The z-score that delineates the middle 96% of all vallues from others is obtained as follows.

$100(1-\alpha)\%=96\% \\ \\ 1-\alpha=0.96 \\ \\ \alpha=1-0.96=0.04 \\ \\ \alpha/2=0.04\2=0.02 \\ \\ z_{0.02}=2.054$

Therefore, the z-scores that delineate the middle 96% of all values from the others is 2.05

4 0

3 years ago