6a) The width of a confidence interval is equal to twice the margin of error.

TRUEFALSE

6b) A simple regression model is used to forecast sales with advertising expenditures. The regression output indicates that the coefficient of advertising expenditures is positive and statistically significant. The output also indicates that the correlation between sales and advertising expenditures is 0.9132. Based on these results, we can conclude that spending more on advertising causes sales to go up.

TRUEFALSE

6c) If a 95% confidence interval for the mean number of hours that students study per week is [18 23], then there is a 95% probability that a randomly selected student will study between 18 to 23 hours per week.

TRUEFALSE

6d) If the level of confidence increases from 90% to 95%, the margin of error will increase

TRUEFALSE

6e) If the correlation between random variables X and Y is +0.8, then when X increases by 1, Y increases by 0.8.

TRUEFALSE

6f) R-Square determines whether or not the overall regression equation is statistically significant.

TRUEFALSE

6g) Type 2 error in hypothesis testing is failing to reject the null hypothesis when it is false.

TRUEFALSE