Question

A survey of 50 retail stores revealed that the average price of a microwave was $375, with a sample standard deviation of $20. Assuming the population is normally distributed, what is the 95% confidence interval to estimate the true cost of the microwave? Select one: a. $323.40 to $426.60 b. $328.40 to $421.60 c. $350.80 to $395.80 d. $369.31 to $380.69

Answer 1

Answer:

(D) $369.31 to $380.69

Explanation:

The formula is x ± t (s/√n)

x = 375

t = 2.010

s = 20

n = 50

Then,

375 ± 2.010 (20/√50)

= 375 ± 5.69