Question

When a survey​ asked, "About how many hours per week do you spend sending and answering​ e-mail?" the 7 females in the survey sample of age at least 80 had the following responses. Use the data to complete parts a through c. 0 0 1 2 8 10 15 a. Using​ technology, find the sample​ mean, standard​ deviation, and the standard error of the sample mean. The sample mean is 4.86. ​(Round to two decimal places as​ needed.) The sample standard deviation is 4.63. ​(Round to two decimal places as​ needed.) The standard error of the sample mean is 1.75. ​(Round to two decimal places as​ needed.) b. Using​ technology, find and interpret a 90​% confidence interval for the population mean. The 90​% confidence interval for the population mean is left parenthesis nothing comma nothing right parenthesis . ​(Round to one decimal place as​ needed.) Interpret the confidence interval from the previous step. Choose the correct answer below. A. There is 0.95​% confidence that the population mean for the number of hours per week people spend sending and answering​ e-mail is between these two values. B. There is 90​% confidence that the population mean for the number of hours per week people spend sending and answering​ e-mail is between these two values. Your answer is correct.C. There is 0.90​% confidence that the population mean for the number of hours per week people spend sending and answering​ e-mail is between these two values. D. Approximately 90​% of the population send and answer​ e-mail between these two values in hours per week. c. Explain why the population distribution may be skewed right. If this is the​ case, is the interval you obtained in part b​ useless, or is it still​ valid? Explain why the population distribution may be skewed right. Choose the correct answer below. A. Since there will be many women that are at least 80 years of age who do not use​ e-mail at all and nobody who uses​ e-mail frequently, the distribution is likely to be skewed right.   Your answer is not correct.B. Since there will be many women that are at least 80 years of age who do not use​ e-mail at all and many who use​ e-mail frequently, the distribution is likely to be skewed right.   C. Since there will be many women that are at least 80 years of age who do not use​ e-mail at all but some who use​ e-mail frequently, the distribution is likely to be skewed right.   This is the correct answer. If the population distribution is skewed​ right, is the interval you obtained in b​ useless, or is it still​ valid? Valid Your answer is correct. Useless

Answer 1

Following is the output of descriptive statistics:

Descriptive statistics
	X
count	7
mean	5.14
sample standard deviation	5.90
sample variance	34.81
minimum	0
maximum	15
range	15

So we have

The standard error is

(b)

Following is the output of confidence interval generated by excel

Descriptive statistics
	X
count	7
mean	5.14
sample standard deviation	5.90
sample variance	34.81
minimum	0
maximum	15
range	15
confidence interval 90.% lower	0.81
confidence interval 90.% upper	9.48
half-width	4.33

The 90% confidence interval is (0.8, 9.5).

B. There is 90​% confidence that the population mean for the number of hours per week people spend sending and answering​ e-mail is between these two values.

C. Since there will be many women that are at least 80 years of age who do not use​ e-mail at all but some who use​ e-mail frequently, the distribution is likely to be skewed right. 

Useless