Question

A researcher took a random sample of 12 two-slice toasters and found an average price of $53.10 with a standard deviation of $12.90. Assuming we have Normal data, construct a 90% confidence interval for the mean price for two-slice toasters. Also find the margin of error. Round your answers to 2 decimal places.

Answer 1

Solution :

Given that,

t /2,df = 1.796

Margin of error = E = t/2,df * (s /n)

= 1.796 * (12.90 / 12)

Margin of error = E = 6.69

The 90% confidence interval estimate of the population mean is,

- E < < + E

53.10 - 6.69 < < 53.10 + 6.69

46.41 < < 59.79

(46.41 , 59.79)