A consumer wanted to estimate her average monthly credit card debt. She took a random sample of monthly credit card statements and recorded the total monthly balance. A histogram of the balances is shown:

a. A 95% confidence interval for the mean credit card balance is shown. Interpret this confidence interval.

b. A log transformation of the data shows a more Normally distributed data set. A 95% confidence interval for the log (base 10) of the credit card balances is shown. Convert the limits back into dollars by raising 10 to the power given as the limit. Report and interpret the confidence interval for the geometric mean.

c. Which interval is narrower?

d. Which interval would you use if you wanted to report on the mean consumer credit card balance for all months? Explain.

Transcribed Image Text:

8 1000 2000 3000 4000 5000 6000 7000 Balance (dollars) Frequency 2.