3. Which of the following statements is true with respect to a simple linear regression model? a. The percent of variation in the dependent variable that is explained by the regression model is equal to the square of the correlation coefficient between the x and y variables b. If the correlation coefficient between the x and y variables is negative, the sign on the regression slope coefficient will also be negative C. If the correlation between the dependent and the independent variable is determined to be significant, the regression model for y given x will also be significant d. All of the above are true 4. A large retail company gives an employment screening test to all prospective employees. If a prospective employee receives a report saying that she scored at the 40th percentile: a. she scored above the median b. she scored better than 40 percent of people who took the test c. she scored in the top 40 percent of people who took the test d. her z score was a 40 5. Which of the following statements is true with respect to the t-distribution? a. The t-distribution is symmetrical. b. The exact shape of the t-distribution depends on the number of degrees of freedom. The t-distribution is more spread out than the standard normal distribution. d. All of the above are true. 6. A scatter plot is useful for identifying a linear relationship between the independent and dependent variable, but it is not particularly useful if the relationship is curvilinear. a) True b) False 7. When using a 95% confidence interval for a mean, the area in the upper tail of the distribution that is outside the interval is 5%. a) True b) False 8. A local medical center has advertised that the mean wait for services will be less than 15 minutes. Given this claim, the hypothesis test for the population mean should be a one-tailed test with the rejection region in the lower (left-hand) tail of the sampling distribution. a) True b) False 9. The standard normal distribution table provides probabilities for the area between the Z-value and the population mean. a) True b) False 10. When a market research manager records the number of potential customers who were surveyed indicating that they like the product design, the random variable-number who like the design-is a discrete random variable. a) True b) False