Questions from Business Statistics

Q: a. What is the difference between a prediction interval and a

a. What is the difference between a prediction interval and a confidence interval? b. Which type of interval should you use to learn about the mean spending habits of your typical customer? c. Which t...

Q: a. What is the standard error for prediction? b

a. What is the standard error for prediction? b. Why is the standard error for prediction even larger than the standard deviation S?

Q: a. What would you change in the computation of a two

a. What would you change in the computation of a two-sided 95% prediction interval to find a two sided 99% prediction interval instead? b. What would you change in the computation of a two-sided 95% p...

Q: a. How many degrees of freedom are there for a single

a. How many degrees of freedom are there for a single sample of size n? b. What accounts for the degree of freedom lost? c. How many degrees of freedom should you use if the standard error is known ex...

Q: a. Describe the two assumptions needed for the confidence interval statement

a. Describe the two assumptions needed for the confidence interval statement to be valid. b. For each assumption, give an example of what could go wrong if it were not satisfied. c. How does the centr...

Q: a. What is the relative frequency interpretation of the correctness of

a. What is the relative frequency interpretation of the correctness of a confidence interval? b. What is the “lifetime track record” interpretation of the correctness of many confidence intervals?

Q: a. What is the purpose of hypothesis testing? b

a. What is the purpose of hypothesis testing? b. How is the result of a hypothesis test different from a confidence interval statement?

Q: a. What is a one-sided test? b

a. What is a one-sided test? b. What are the hypotheses for a one-sided test? c. When are you allowed to perform a one-sided test? What should you do if you are not sure if it is allowed? d. If you pe...

Q: Consider annual salary as the Y variable and experience as the X

Consider annual salary as the Y variable and experience as the X variable. a. Draw a scatterplot and describe the relationship. b. Find the correlation coefficient. What does it tell you? Is it approp...

Q: a. How is a one-sided test performed based on

a. How is a one-sided test performed based on a confidence interval? b. How is a one-sided test performed based on the t-statistic?