Question

An automobile manufacturer has given its jeep a 46.3 miles/gallon (MPG) rating. An independent testing firm has been contracted to test the actual MPG for this jeep since it is believed that the jeep has an incorrect manufacturer's MPG rating. After testing 200 eeps, they found a mean MPG of 46.7 . Assume the population variance is known to be 6.25 . A level of significance of 0.05 will be used. State the null and alternative hypotheses.

Answer 1

: Mean MPG rating of the Jeep

Hypothesized mean = 46.3 MPG(Mean rating given by the automobile manufacturer)

To test : Actual MPG for this jeep since it is believed that the jeep has an incorrect manufacturer's MPG rating i.e

To test : (This goes as a part of alternate hypothesis)

Null hypothesis : H_o :

Alternate hypothesis : H₁ :

Two tailed test:

As population standard deviation is known

Given,

sample size : n= 200

Sample mean : = 46.7

population variance = 6.25

For two tailed test :

As P-Value i.e. is greater than Level of significance i.e (P-value:0.3654 > 0.05:Level of significance); Fail to Reject Null Hypothesis
There is not sufficient evidence to conclude that the  jeep has an incorrect manufacturer's MPG rating