The average selling price of a smartphone purchased by a random sample of

32 customers was $315.

Assume the population standard deviation was

$34.

a. Construct a 90% confidence interval to estimate the average selling price in the population with this sample.

b. What is the margin of error for this interval?

a. The 90% confidence interval has a lower limit of =

and an upper limit of=

(Round to the nearest cent as needed.)

b. The margin of error is

(Round to the nearest cent as needed.)