A savings and loan association needs information concerning the checking account balances of its local customers. A random sample of 20 accounts was checked and yielded a mean balance of $664.14 and a standard deviation of 235.29. Assume the data is normally distributed. Find a 98% confidence interval for the true mean checking account balance for local customers. State the following:

Critical t/z score (which one?): ___________ value __________

Margin of error: E=_______(nearest cent)

Write the confidence interval as indicated below, rounding values to the nearest cent.
Confidence Interval:_________<μ<_____________