Question

. The average expenditure on Valentine’s Day was expected to be $100.89. Do male and female consumers differ in the amounts they spend? The average expenditure in a sample survey of 40 male consumers was $135.67, and the average expenditure in a sample survey of 30 female consumers was $68.64. Based on past surveys, the standard deviation for male consumers is assumed to be $35, and the standard deviation for female consumers is assumed to be $20. a. What is the point estimate of the difference between the population mean expenditure for males and the population mean expenditure for females? b. Develop a 96% confidence interval for the difference between the two population means. (Assume equal variance)

Answer 1

let X and Y represent the male and female respectively

given

a.)

Point estimate of the difference between the population mean expenditure for males and the population mean expenditure for females:

b.)

Critical value at 96% confidence (Z_a/2)=2.05

(use standard normal table)

Margin of error(E):

96% confidence interval: