9. A die is rolled 30 times and the results are recorded in the table.

Number Rolled 1 2 3 4 5 6

Frequency 6 9 4 4 2 5

A goodness-of-fit chi-square test is to be used to test the null hypothesis that the die is fair. At a significance level of ? = 0.01, what is the value of chi-square and the appropriate conclusion?

a. ?2= 5.6; fail to reject the null hypothesis

b.?2= 5.6; reject the null hypothesis

c.?2= 11.2; fail to reject the null hypothesis

d.?2= 11.2; reject the null hypothesis

e.?2= 15.33; fail to reject the null hypothesis

10. A random sample of 200 employees at a specific company is asked to state their gender and annual salary. The results are recorded in the table.

Gender $50,000 $75,000 $100,000 >$100,000

Male 29 34 12 20

Female 41 44 6 14

A chi-square test is used to test the null hypothesis that gender and salary are independent. Which statement is correct?

a. Fail to reject H0at the 0.10 significance level.

b.Fail to reject H0at the 0.5 significance level.

c.Reject H0at the 0.01 significance level.

d.Reject H0at the 0.05 significance level.

e.Reject H0at the 0.001 significance level.

11. A popular infomercial wants to know the proportion of viewers that prefer gold to silver jewelry. Viewers are asked to text "gold" or "silver" to a provided number. Seventy-seven percent of the 5,000 people that responded texted "gold." Which condition for inference has NOT been met?

a.All conditions appear to be met.

b.N > 10n

c.np ? 10 and n(1 - p) ? 10

d.Inference about a proportion is the objective.

e.The sample is an SRS of the population.

12. An experiment was conducted to compare broadleaf seedling growth by treating the seedling soil weeds with one of two fertilizers. Thirty of 75 seedlings were randomly chosen to receive Fertilizer X. The rest received Fertilizer Y. The heights were recorded for each seedling, in centimeters, at the end of the study. The results obtained are shown.

Fertilizer X: X?₁= 72.4 cm, s₁= 9 cm

Fertilizer Y: X?₂= 86.1 cm, s₂= 8 cm

We wish to determine whether there is a difference in height for the seedlings treated with the different herbicides. To answer this question, we decide to test the hypotheses H₀: ?₂? ?₁= 0 and H_a: ?₂? ?₁? 0. Find the 95% confidence interval for ?₂? ?₁and make a conclusion based on that confidence interval.

a.The 95% confidence interval is 13.7 4.065. I would not reject the null hypothesis of no difference at the 0.05 level.

b.The 95% confidence interval is 13.7 9.63. I would not reject the null hypothesis of no difference at the 0.05 level.

c.The 95% confidence interval is 13.7 4.065. I would reject the null hypothesis of no difference at the 0.05 level.

d.The 95% confidence interval is 13.7 9.63. I would reject the null hypothesis of no difference at the 0.05 level.

e.The 95% confidence interval is 13.7 17.75. The p-value is less than 0.05.

13. The time, in seconds, it takes a random sample of 30 dogs to perform a specific trick is displayed in the histogram.

O 0 5 10 15 20 25 30 35 40 45 50 55 60 65 Time, seconds12 11 10 8 - 6 Number of Dogs 6 4 2 2 1 0 0-5 6-10 11-15 16-20 21-25 26-30 31-35 36-40 41-45 46-50 51-55 56-60 Time, seconds