STATS ASSIGNMENT MCQ HOMEWORK FALL 2015
Question 1
A powerful women’s group has claimed that men and women differ in attitudes about sexual discrimination. A group of 50 men (group 1) and 40 women (group 2) were asked if they thought sexual discrimination is a problem in the United States. Of those sampled, 11 of the men and 19 of the women did believe that sexual discrimination is a problem. Find the value of the test statistic.
Z = -2.55
Z = -0.85
Z = -1.05
Z = -1.20
Question 2
If we are testing for the difference between the means of 2 related populations with samples of n1 = 20 and n2 = 20, the number of degrees of freedom is equal to
39.
38.
19.
18.
Question 3
Private colleges and universities rely on money contributed by individuals and corporations for their operating expenses. Much of this money is put into a fund called an endowment, and the college spends only the interest earned by the fund. A recent survey of 8 private colleges in the United States revealed the following endowments (in millions of rands): 60.2, 47.0, 235.1, 490.0, 122.6, 177.5, 95.4, and 220.0. What value will be used as the point estimate for the mean endowment of all private colleges in the United States?
R1,447.8
R180.975
R143.042
R8
Question 4
TABLE 10-1
Are Japanese managers more motivated than American managers? A randomly selected group of each were administered the Sarnoff Survey of Attitudes Toward Life (SSATL), which measures motivation for upward mobility. The SSATL scores are summarized below.
American Japanese
Sample size 211 100
Mean SSATL Score 65.75 79.83
Population Std. Dev. 11.07 6.41
Referring to Table 10-1, judging from the way the data were collected, which test would likely be most appropriate to employ?
Paired t test
pooled-variance t test for the difference between two means
F test for the ratio of two variances
Z test for the difference between two proportions
Question 5
TABLE 9-7
A major home improvement store conducted its biggest brand recognition campaign in the company’s history. A series of new television advertisements featuring well-known entertainers and sports figures were launched. A key metric for the success of television advertisements is the proportion of viewers who “like the ads a lot.” A study of 1,189 adults who viewed the ads reported that 230 indicated that they “like the ads a lot.” The percentage of a typical television advertisement receiving the “like the ads a lot” score is believed to be 22%. Company officials wanted to know if there is evidence that the series of television advertisements are less successful than the typical ad (i.e. if there is evidence that the population proportion of “like the ads a lot” for the company’s ads is less than 0.22) at a 0.01 level of significance.
Referring to Table 9-7, the null hypothesis will be rejected if the test statistics is
greater than 2.3263.
less than 2.3263.
greater than -2.3263.
less than -2.3263.
Question 6
In testing for the differences between the means of 2 independent populations where the variances in each population are unknown but assumed equal, the degrees of freedom are
n – 1.
n1 + n2 – 1.
n1 + n2 – 2.
n – 2.
Question 7
Given the following information, calculate the degrees of freedom that should be used in the pooled-variance t test.
s12 = 4 s22 = 6
n1 = 16 n2 = 25
df = 41
df = 39
df = 16
df = 25
Question 8
If you were constructing a 99% confidence interval of the population mean based on a sample of n=25 where the standard deviation of the sample s = 0.05, the critical value of t will be (tick made by mistake)
2.7969.
2.7874.
2.4922.
2.4851.
Question 9
If the p-value is less than ? in a two-tail test,
the null hypothesis should not be rejected.
the null hypothesis should be rejected.
a one-tail test should be used.
no conclusion should be reached.
Question 10
In testing for differences between the means of two related populations, the null hypothesis is
H0 : ? D = 2.
H0 : ? D = 0.
H0 : ? D < 0.
H0 : ? D > 0.
Question 11
TABLE 10-5
To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. The results are given below.
Student Exam score
Before Course (1) Exam Score
After course (2)
1 530 670
2 690 770
3 910 1000
4 700 710
5 450 550
6 820 870
7 820 770
8 630 610
Referring to Table 10-5, the number of degrees of freedom is
14.
13.
8.
7.
Question 12
TABLE 10-5
To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. The results are given below.
Student Exam score
Before Course (1) Exam Score
After course (2)
1 530 670
2 690 770
3 910 1000
4 700 710
5 450 550
6 820 870
7 820 770
8 630 610
Referring to Table 10-5, the value of the standard error of the difference scores is
65.027.
60.828.
22.991.
14.696.
Question 13
The owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club. She would now like to determine whether or not the mean age of her customers is over 30. If so, she plans to alter the entertainment to appeal to an older crowd. If not, no entertainment changes will be made. If she wants to be 99% confident in her decision, what rejection region should she use?
Reject H0 if t < -2.3263.
Reject H0 if t < -2.5758.
Reject H0 if t > 2.3263.
Reject H0 if t > 2.5758.
Question 14
An economist is interested in studying the incomes of consumers in a particular region. The population standard deviation is known to be R1,000. A random sample of 50 individuals resulted in an average income of R15,000. What total sample size would the economist need to use for a 95% confidence interval if the width of the interval should not be more than R100?
n = 1537
n = 385
n = 40
n = 20
Question 15
Private colleges and universities rely on money contributed by individuals and corporations for their operating expenses. Much of this money is put into a fund called an endowment, and the college spends only the interest earned by the fund. A recent survey of 8 private colleges in the United States revealed the following endowments (in millions of rands): 60.2, 47.0, 235.1, 490.0, 122.6, 177.5, 95.4, and 220.0. Summary statistics yield X ? = 180.975 and S= 143.042. Calculate a 95% confidence interval for the mean endowment of all the private colleges in the United States assuming a normal distribution for the endowments.
R180.975 ± R94.066
R180.975 ± R99.123
R180.975 ± R116.621
R180.975 ± R119.586
Question 16
How many tissues should the Kimberly Clark Corporation package of Kleenex contain? Researchers determined that 60 tissues is the mean number of tissues used during a cold. Suppose a random sample of 100 Kleenex users yielded the following data on the number of tissues used during a cold: X ? = 52, S = 22. Using the sample information provided, calculate the value of the test statistic.
t = (52 – 60)/22
t = (52 – 60)/(22/100)
t = (52 – 60)/(22/1002)
t = (52 – 60)/(22/10)
Question 17
Which of the following would be an appropriate null hypothesis?
The mean of a population is equal to 55.
The mean of a sample is equal to 55.
The mean of a population is greater than 55.
Only The mean of a population is equal to 55. and The mean of a population is greater than 55. are appropriate.
Question 18
In testing for differences between the means of 2 related populations where the variance of the differences is unknown, the degrees of freedom are
n – 1.
n1 + n2 – 1.
n1 + n2 – 2.
n – 2.
Question 19
The owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club. She would now like to determine whether or not the mean age of her customers is over 30. If so, she plans to alter the entertainment to appeal to an older crowd. If not, no entertainment changes will be made. Suppose she found that the sample mean was 30.45 years and the sample standard deviation was 5 years. If she wants to be 99% confident in her decision, what decision should she make?
Reject H0.
Accept H0.
Fail to reject H0.
We cannot tell what her decision should be from the information given.
Question 20
The owner of a local nightclub has recently surveyed a random sample of n = 250 customers of the club. She would now like to determine whether or not the mean age of her customers is over 30. If so, she plans to alter the entertainment to appeal to an older crowd. If not, no entertainment changes will be made. The appropriate hypotheses to test are: tick made by mistake
H0 ? ? 30 versus H1 ? < 30.
H0 ? ? 30 versus H1 ? > 30.
H0 :X ? ? 30 versus H1 :X ? < 30.
H0 :X ? ? 30 versus H1 :X ? > 30.
Question 21
TABLE 10-5
To test the effectiveness of a business school preparation course, 8 students took a general business test before and after the course. The results are given below.
Student Exam score
Before Course (1) Exam Score
After course (2)
1 530 670
2 690 770
3 910 1000
4 700 710
5 450 550
6 820 870
7 820 770
8 630 610
Referring to Table 10-5, the value of the sample mean difference is ________ if the difference scores reflect the results of the exam after the course minus the results of the exam before the course.
0
50
68
400
Question 22
