1.A teacher assumed there was a correlation between amount of hours that his students studied before a history class and their grades. The null hypothesis was that the correlation between the study hours and grades was:

a.Positive 1.0

b.Negative 1.0

c.Zero

d.Positive 0.50

1.A teacher hypothesized that the on average, his students consumed two bottles of soda per day. Imagine that the teacher recorded soda consumption for every student: the confidence interval of soda consumption was (1.6, 2.4). Can you reject the teacher's null hypothesis at 95%?

a.Yes

b.No

c.We cannot tell from the given information

1.If a statistical test result is significant at the 0.01 level, then we can conclude:

a.It is not significant at 0.05 level

b.It is not significant at 0.10 level

c.We do not know if it will be significant at 0.05 level

d.It must be significant at 0.05 level

1.___ is the probability of accepting a false null hypothesis.

a.1-

b.

c.

d.1-

1.A teacher was interested in knowing the amount of physical activity that his students were engaged in daily. He randomly sampled six students in his class and recorded the number of minutes that they exercised in the past day. The numbers were 30mins, 40 mins, 60 mins, 80 mins, 20 mins, and 85 mins. What's the sample standard deviation? (show work)

1.A teacher was interested in knowing the amount of physical activity that his students were engaged in daily. He randomly sampled six students in his class and recorded the number of minutes that they exercised in the past day. The numbers were 30mins, 40 mins, 60 mins, 80 mins, 20 mins, and 85 mins. This teacher posed a null hypothesis that the average amount of physical activity of his students should be 60 mins per day. What is the absolute value of calculated t that we use for testing the null hypothesis? (show work)

1.Which of the following descriptions about t distribution is correct (select only one)?

a.Compared to the normal distribution, the t distribution has more values at the top and fewer at the tail.

b.Compared to the normal distribution, the t distribution has fewer values at the top and more values at the tail.

c.T distribution always has the same shape with a normal distribution

d.T distribution is extremely right-skewed

1.A professor posed a hypothesis that there was no significant difference between boys and girls on their soda consumption per day in an elementary school. He randomly sampled 25 boys and 25 girls. The mean soda consumption for boys was 40 oz per day and the standard deviation was 5. The mean soda consumption for girls was 30 oz per day and the standard deviation was 5. What is the standard error of the difference in means? (show work)

1.A professor wants to test all possible pairwise comparisons among all four means. If we need to maintain an "experiment-wise" alpha of 0.01, what is the error rate per comparison after applying Bonferroni correction? (show work)

1.1- is the probability of_______

a.Rejecting a true null hypothesis

b.Accepting a true null hypothesis

c.Accepting a false null hypothesis

d.Rejecting a false null hypothesis

1.Which of the following descriptions are correct regarding power (select all that apply)?

a.Changing from a one-tailed test to a two-tailed test can increase power

b.Increasing sample size can increase power

c.Increasing standard deviation will decrease power

d.Changing from a one-tailed test to a two-tailed test, or changing from a two-tailed test to a one-tailed test will not change power