Question

The next four questions refer to data on the number of emails considered important received by Whitey college students within a 24-hour period. A random sample was collected by surveying students about the number of received emails they considered important within a 24-hour period. Students were also surveyed on whether they active Facebook users.

1) Which of the following best describes a 95% confidence interval for the average number of important emails received by a Whitey student within a 24-hour period?

2) Which of the following is the best estimate for the proportion of Whitey students who actively use Facebook:

	a: 27%
	b: 73%
	c: 2.67
	d: 278

Q3. What is the best estimate for the standard deviation of the number of important emails received in a 24-hour period by a Whitey student who is an active Facebook user?

Q4 Which of the following is the best estimate for the proportion of those who receive at most one important e-mail in a 24hour period (i.e., either zero or one important emails) among Whitey students who actively use Facebook?

	a: less than one quarter
	b: at least one quarter but less than one third
	c: at least one third but less than one half
	d: at least one half

# of important emails
received in a 24hr period	active Facebook user
2	Yes
3	Yes
1	Yes
2	No
1	Yes
1	Yes
2	Yes
3	Yes
3	Yes
2	No
4	Yes
3	Yes
0	No
2	Yes
2	Yes
2	Yes
4	Yes
6	No
2	Yes
4	Yes
0	No
4	Yes
3	Yes
3	Yes
2	Yes
5	No
1	Yes
2	Yes
2	Yes
1	No
0	Yes
1	Yes
2	Yes
0	Yes
4	Yes
5	No
1	Yes
2	Yes
5	No
1	Yes
3	Yes
2	Yes
3	Yes
3	Yes
2	No
2	Yes
3	No
0	Yes
0	No
2	Yes
2	Yes
1	Yes
2	Yes
3	No
2	No
2	Yes
1	Yes
2	Yes
1	Yes
4	No
4	No
0	Yes
2	No
4	No
3	Yes
2	Yes
3	Yes
2	Yes
2	Yes
2	Yes
1	Yes
4	Yes
3	No
2	Yes
3	Yes
3	Yes
4	Yes
2	No
2	Yes
3	Yes
2	Yes
0	No
0	Yes
2	Yes
1	No
1	No
1	Yes
2	Yes
0	No
4	Yes
2	Yes
5	Yes
4	No
1	Yes
1	Yes
4	Yes
1	No
2	Yes
2	Yes
1	Yes
0	No
3	Yes
2	No
1	Yes
1	Yes
1	Yes
3	Yes
3	Yes
2	Yes
0	Yes
2	Yes
1	Yes
4	Yes
5	Yes
1	Yes
2	Yes
5	Yes
2	Yes
1	No
2	Yes
3	Yes
2	Yes
1	Yes
5	No
2	Yes
2	No
3	Yes
2	No
2	No
1	Yes
0	No
3	Yes
6	No
1	Yes
1	Yes
2	No
5	Yes
6	No
2	Yes
5	Yes
3	No
6	Yes
3	Yes
3	No
0	No
5	Yes
1	Yes
5	No
2	Yes
4	Yes
3	Yes
1	Yes
0	No
1	Yes
1	Yes
1	Yes
3	No
3	Yes
2	Yes
1	Yes
0	No
2	No
1	Yes
2	No
0	Yes
2	Yes
5	Yes
0	Yes
4	Yes
0	No
1	Yes
2	Yes
0	No
4	Yes
2	No
4	No
3	Yes
1	No
2	Yes
3	Yes
0	Yes
2	Yes
3	Yes
4	Yes
4	Yes
4	Yes
0	Yes
3	Yes
3	Yes
2	No
3	Yes
3	Yes
4	Yes
6	Yes
2	Yes
2	Yes
2	Yes
1	Yes
5	Yes
3	Yes
4	No
2	Yes
2	Yes
5	Yes
0	No
0	No
0	No
3	Yes
0	Yes
1	Yes
2	Yes
2	No
4	Yes
3	Yes
1	Yes
1	No
0	No
2	Yes
1	Yes
2	Yes
3	Yes
3	No
2	Yes
0	Yes
3	Yes
2	Yes
0	Yes
4	No
3	Yes
3	Yes
2	Yes
1	Yes
1	Yes
2	No
1	No
0	No
2	No
4	Yes
3	Yes
2	Yes
1	No
3	Yes
0	No
0	Yes
5	Yes
1	Yes
4	Yes
3	Yes
4	No
3	No
2	Yes
3	Yes
1	Yes
2	Yes
2	Yes
2	Yes
1	No
4	Yes
5	No
0	No
2	Yes
2	Yes
0	No
3	Yes
2	No
4	Yes
3	Yes
1	Yes
4	Yes
3	Yes
1	Yes
1	No
2	Yes
0	Yes
2	Yes
0	No
3	Yes
1	Yes
2	Yes
2	No
2	Yes
1	Yes
2	Yes
2	Yes
2	No
1	Yes
3	Yes
2	No
3	Yes
2	Yes
3	Yes
3	Yes
4	Yes
1	Yes
2	Yes
2	Yes
0	Yes
5	Yes
1	Yes
0	No
2	Yes
1	Yes
0	No
4	Yes
2	Yes
1	Yes
3	Yes
2	No
2	No
3	No
1	Yes
4	No
2	Yes
1	Yes
0	Yes
2	Yes
8	No
4	Yes
5	No
4	Yes
1	Yes
1	No
1	Yes
2	Yes
2	No
3	Yes
1	Yes
4	Yes
4	Yes
1	Yes
1	Yes
3	Yes
2	Yes
2	Yes
1	Yes
1	Yes
0	No
2	Yes
1	No
1	Yes
1	Yes
2	Yes
3	No
0	Yes
1	Yes
1	Yes
0	Yes
0	Yes
3	Yes
5	Yes
0	Yes
3	Yes
1	Yes
2	Yes
5	No
1	No
2	Yes
4	No
3	Yes
0	Yes
1	Yes
0	Yes
2	Yes
0	No
4	No
1	No
2	Yes
2	No
5	No
5	Yes
2	No
1	Yes
2	Yes
2	No
2	No
3	Yes
2	Yes
0	Yes
4	No
2	Yes
1	Yes
2	Yes

Answer 1

Answer to question# 1)

The best way to interpret 95% confidence interval is as follows:

If several samples are taken 95% of them will contain the true mean number of important emails received by a Whitey student within 24 hour period

.

Answer to question# 2)

There are 278 active FB users out of total 382

Proportion = (278/382) *100

Proportion = 72..77% ~ 73%

.

Answer to question# 3)

The best estimate of standard deviation of active fb users I;

Use the excel function =stdev(range of values)

Press enter , we get standard deviation = 1.3096

.

Answer too question# 4)

Out of total 278 active users, 90 of them get either 0 or 1 important mails

Thus proportion = 90 /278 = 0.3237

This values lies between quarter and one third

Hence the second answer choice is correct