In: Statistics and Probability
Data were collected on the amount spent for lunch by 64 customers at a major Houston restaurant. The sample provided a sample mean of $21.5. Based upon past studies the population standard deviation is known with σ = $6. Develop a 99% confidence interval estimate of the mean amount spent for lunch.
Solution :
Given that,
Sample size = n = 64
Z/2 = 2.576
Margin of error = E = Z/2* ( /n)
= 2.576 * (6 / 64)
= 1.93
At 99% confidence interval estimate of the population mean is,
- E < < + E
21.5 - 1.93 < < 21.5 + 1.93
19.57 < < 23.43
( 19.57, 23.43)