The standard deviation of test scores on a certain achievement test is

10.7

.A random sample of

100

scores on this test had a mean of

73.8

.Based on this sample, find a

90%

confidence interval for the true mean of all scores. Then give its lower limit and upper limit.

Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult alist of formulas.)