Question

An automobile manufacturer has given its van a 47.2 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the actual MPG for this van since it is believed that the van has an incorrect manufacturer's MPG rating. After testing 250 vans, they found a mean MPG of 47.0. Assume the population standard deviation is known to be 1.9. A level of significance of 0.02 will be used. Find the value of the test statistic. Round your answer to two decimal places.

Answer 1

Test statistic = 1.664

Explanation:

The hypothesis :

H0 : μ = 47.2

H1 : μ ≠ 47.2

Given that :

Sample mean, xbar = 47

Sample size, n = 250

Standard deviation, σ = 1.9

The test statistic :

(xbar - μ) ÷ (σ/√(n))

T = (47 - 47.2) ÷ (1.9/√(250))

T = (0.2 / 0.1201665)

Test statistic = 1.664