Question

A fast food restaurant executive wishes to know how many fast food meals adults eat each week. They want to construct a 95% confidence interval for the mean and are assuming that the population standard deviation for the number of fast food meals consumed each week is 1.4. The study found that for a sample of 1537 adults the mean number of fast food meals consumed per week is 6.4. Construct the desired confidence interval. Round your answers to one decimal place.

Answer 1

Solution :

Given that,

Point estimate = sample mean = = 6.4

Population standard deviation = = 1.4

Sample size = n = 1537

At 95% confidence level the z is ,

Z_/2 = Z_0.025 = 1.96

Margin of error = E = Z_/2* ( /n)

=1.96* ( 1.4/ 1537 )

= 0.1

At 95% confidence interval estimate of the population mean is,

- E < < + E

6.4 - 0.1 < < 6.4 + 0.1

6.3 < < 6.5

( 6.3 , 6.5 )