The y-intercept of a regression equation is interpreted as:
A) The predicted value of y when x equals 0.
B) The change in y for a one unit change in x.
C) The amount of variation in y explained by x.
Which of the following correlations would have the weakest linear relationship?
A) r = 0.9
B) r = -0.7
C) r = -0.1
D) r = 0.6
In general, which is more likely to contain the unknown population mean?
A) A 90% confidence interval
B) A 95% confidence interval
C) A 99% confidence interval
D) They are all equally likely
Suppose a 95% confidence interval for the proportion of Americans who smoke is 0.178 to 0.242. Which one of the following statements is NOT true?
A) It is reasonable to say that more than 25% of Americans smoke.
B) It is reasonable to say that less than 25% of Americans smoke.
C) It is reasonable to say that more than 17% of Americans smoke.
D) An "acceptable" hypothesis is that about 19% of Americans smoke.
Suppose there is a project to study the effectiveness of a new treatment for high cholesterol. To test whether the new treatment lowers cholesterol level, cholesterol readings were recorded on same participant before and after a 10-week treatment period. What kind of test would you recommend for this study?
A) a two sample t-test
B) a paried t-test
C) a two proportion test
D) an unpooled t-test
Identify whether the comparison is based on two independent samples or paired data:
We test if the average number of hours studied for college freshman is different from the average number of hours studied for seniors in college.
A) Paired
B) Independent
Based on the number and types of variables present, select the most appropriate display for each of the following:
Rent charged (in dollars) and apartment size (in sq. ft.) of a sample of one-bedroom apartments in State College.
A) Bar Graph
B) Histogram
C) Two-way table
D) Scatterplot
E) Side-by-Side Boxplots
Based on the number and types of variables present, select the most appropriate display for each of the following:
Whether a person is a vegetarian and Gender.
A) Bar Graph
B) Histogram
C) Two-way table
D) Scatterplot
E) Side-by-Side Boxplots