Question

A consumer group conducts a study to compare the average mileages (in units of miles per gallon, mpg) of two popular car brands achieved in road tests. A random sample of 5 cars from Brand 1 were tested, yielding mean mileage xbar1= 29.5 mpg and sample standard deviation s₁ = 7.4 mpg. A random sample of 8 cars from Brand 2 were tested, yielding mean mileage xbar2= 31.6 mpg and s₂ = 8.4 mpg. Assume that two populations from which the samples are drawn are normally distributed. At the 5 percent significance level, do the data provide sufficient evidence to conclude that there is no difference between average mileages of Brand 1 cars and Brand 2 cars?

Answer 1

Solution-

by the given information and summarised data to test the given claim t test is calculated-

◆ Test calculation and results-

above test results that the null hypothesis Ho is not rejected.

So, there is enough evidence to support the claim that there is no difference between average mileages of brand 1 cars and brand 2 cars.