Question

The cost of a meal for a sample of eight customers was recorded. The results (in Rands) were as follows:130.11, 129.85, 130.05, 128.53, 129.99, 129.85, 130.18, 129,98
a) Estimate a 90% confidence interval for the true average of cost of a meal. (3)
b) Calculate the length of the confidence interval. (1)
c) Provide the correct interpretation of the confidence interval you have calculated in a). (1)

Answer 1

$$(102.2,125)$$

$$125-102.2=22.8$$

Average cost of food (in rand) is not less than 102.2 and not more than 125.