1. Conventionally, we will fail to reject the null hypothesis if the probability value is:
a. Greater than or equal to 0.05
b. Less than 0.05
c. Less than 0.01
d. Less than 0.95
2. 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
3. Which of the following can increase the rate of Type I error? (select all that apply)
a. Adjusting the significance level from 0.01 to 0.05
b. Adjusting the significance level from 0.05 to 0.01
c. Adjusting the significance level from 0.10 to 0.05
d. Adjusting the significance level from 0.05 to 0.10
4. At which of the following significance levels do you feel the most confident to reject the null hypothesis?
a. 0.05
b. 0.01
c. 0.95
d. 0.99
5. 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
6. 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
7. ___ is the probability of accepting a false null hypothesis.
a. 1-β
b. β
c. α
d. 1- α
8. 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)
10. 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