Question

Congress regulates corporate fuel economy and sets an annual gas mileage for cars. A company with a large fleet of cars hopes tomeet the 2011 goal of 30.2 mpg or better for their fleet of cars. To see if the goal is being met, they check the gasoline usage for 50 company trips chosen at random, finding a mean of 32.12 mpg and a standard deviation of 4.83 mpg. Is this strong evidence that they have attained their fuel economy goal

Answer 1

Answer:

There is sufficient evidence that fuel economy goal has been attained.

Step-by-step explanation:

The hypothesis :

H0 : μ < 30.2

H1 : μ ≥ 30.2

The test statistic :

(xbar - μ) ÷ (s/√(n))

xbar = 32.12 ; s = 4.83 ; n = 50

Test statistic :

(32.12 - 30.2) ÷ (4.83/√(50))

1.92 ÷ 0.6830651

T = 2.811

Using the Pvalue from test statistic calculator :

Since we used the sample standard deviation, we use the T distribution

df = n - 1 = 50 - 1 = 49

Pvalue(2.811, 49) ; one tailed = 0.00354

At α = 0.05

Pvalue < α ; then we reject the null and conclude that there is sufficient evidence that fuel economy goal has been attained