1) A study of violence and peer acceptance reported descriptive results for male and female students. The average age for 17 male students was 15.79 with a standard deviation of 2.01. Construct a 99% confidence interval for the average age of male students. What is the lower bound for this confidence interval?
a. 15.36
b. 13.96
c. 14.50
d. 14.32
2) A research study interested in the adoption of the "urban lifestyle" among delinquent youths surveyed 1,000 delinquent youths and found that their average on the "urban lifestyle scale" is 7.65 with a standard deviation of 1.01. What's the upper bound for a 95% confidence interval?
a. 7.59
b. 7.71
c. 7.04
d. 7.96
3) The US Census shows that 35% of Americans have a passport. We think that in Phoenix, fewer people have passports (Phoenix is a resort town after all, why travel?). We take a sample of 1500 Phoenix residents and find that 31% have a passport. Conduct a hypothesis test around a proportion that tests whether fewer Phoenix residents have passports than the overall US. Use alpha = 0.05. What would be your alternative hypothesis?
a. H1: p < 0.31
b. H1: p > 0.31
c. H1: p < 0.35
d. H1: p > 0.35
4) The US Census shows that 35% of Americans have a passport. We think that in Phoenix, fewer people have passports (Phoenix is a resort town after all, why travel?). We take a sample of 1500 Phoenix residents and find that 31% have a passport. Conduct a hypothesis test around a proportion that tests whether fewer Phoenix residents have passports than the overall US. Use alpha = 0.05. What do you conclude?
a. Fail to reject the null hypothesis.
b. Reject the null hypothesis.
|
|
Driver post-stop perceived race or ethnicity
|
Total
|
|
White
|
Unknown
|
Native American
|
Hispanic
|
Black
|
Asian
|
|
Driver arrested
|
no
|
18005
|
261
|
357
|
5240
|
1867
|
552
|
26282
|
|
yes
|
1010
|
12
|
67
|
562
|
168
|
22
|
1841
|
|
Total
|
|
19015
|
273
|
424
|
5802
|
2035
|
574
|
28123
|
Using the table above, answer the following 2 questions:
5) What is the probability of being arrested or Asian? P(Yes OR Asian)
a. 0.085
b. 0.076
c. 0.087
d. 0.091
6) What is the probability of not being arrested and being Hispanic? P(No Arrest & Hispanic)?
a. 0.211
b. 0.167
c. 0.188
d. 0.192
7) Say you have a table with 4 rows and 2 columns. Using α = 0.01, what would your χ2 critical value be?
a. 3.84
b. 7.81
c. 11.34
d. 12.59
8) Using the following table, what would be the expected frequency for "Routine & Pretty Happy"? Is Life Exciting or Dull * General Happiness Crosstabulation
Count
|
|
General Happiness
|
Total
|
|
Very Happy
|
Pretty Happy
|
Not Too Happy
|
|
Is Life Exciting or Dull
|
Exciting
|
195
|
218
|
21
|
434
|
|
Routine
|
98
|
338
|
61
|
497
|
|
|
Dull
|
2
|
12
|
26
|
40
|
|
Total
|
|
295
|
568
|
108
|
971
|
a. 151
b. 290.7
c. 23.4
d. 55.3
9) Calculate the χ2 for the following table.
Is Life Exciting or Dull * General Happiness Crosstabulation
Count
|
|
General Happiness
|
Total
|
|
Very Happy
|
Pretty Happy
|
Not Too Happy
|
|
Is Life Exciting or Dull
|
Exciting
|
195
|
218
|
21
|
434
|
|
Routine
|
98
|
338
|
61
|
497
|
|
|
Dull
|
2
|
12
|
26
|
40
|
|
Total
|
|
295
|
568
|
108
|
971
|
a. 196.02
b. 156.89
c. 205.36
d. 186.33
10) Given the χ2 you found in the above table, would you reject or fail to reject the null hypothesis? Use an alpha level of 0.01.
a. Reject the null hypothesis
b. Fail to reject the null hypothesis