Question

A savings and loan association needs information concerning the checking account balances of its local customers....

A savings and loan association needs information concerning the checking account balances of its local customers. A random sample of 14 accounts was checked and yielded a mean balance of $664.14 with a standard deviation of $297.29. Find a 90% confidence interval for the true mean checking account balance for local customers. Assume the variable is normally distributed. Give the lower limit of the confidence interval as your answer below. Round to two decimal places.

Homework Answers

Answer #1

Mean = 664.14

Sample size (n) = 14

Standard deviation (s) = 297.29

Confidence interval(in %) = 90

Since we know that

Required confidence interval

Required confidence interval = (664.14-140.6337, 664.14+140.6337)

Required confidence interval = (523.51, 804.77)

the lower limit of the confidence interval : 523.51

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