Question

A consumer group surveyed the prices for white cotton extra-long twin sheet sets in five different department stores and reported the average price as $16 with standard deviation $3.81. Assume that the population is normal and has a standard deviation equal to $3.81. 9. Provide a 95% confidence interval in order to estimate the average price of the white cotton extra-long twin sheets. z* is 1.96

Answer 1

95% confidence interval in order to estimate the average price of the white cotton extra-long twin sheets.

(12.6604 ,19.3396)

Explanation:

Step(i):-

Given that mean of the sample = 16

Given that the standard deviation of the sample = 3.81

The standard deviation of the Population = 3.81

Level of significance = 0.05

Step(ii):-

95% confidence interval in order to estimate the average price of the white cotton extra-long twin sheets.

`(x^(-) - Z_(0.05) (S.D)/(√(n) ) , x^(-) + Z_(0.05) (S.D)/(√(n) ) )`

(
`(16 - 1.96 ((3.81))/(√(5) ) , 16 +1.96 ((3.81))/(√(5) ))`

( 16 - 3.3396 , 16 + 3.3396)

(12.6604 ,19.3396)

Final answer:-

95% confidence interval in order to estimate the average price of the white cotton extra-long twin sheets.

(12.6604 ,19.3396)