Question

A car company wishes to test the claim that at an average of 55 mph, the stopping distance for auto brakes is 130 ft. In a random sample of 21 individuals that were tested for their breaking distance were recorded, a sample mean of 114 ft. and with a standard deviation is recorded as 20 ft. At the 5% level of significance, test the claim that the stopping distance for a car traveling at 55 mph is less than the stated 130 ft.

What is the Null hypothesis (H0); Alternate hypothesis (H1); and the direction of the test?                            [ Select ]                       ["mu=130; mu>130; left tail Test", "mu=130; mu<130; two tail Test", "mu=130; mu<130; left tail Test", "mu=130; mu<130; right tail Test"]      

Which distribution is used in this case?                            [ Select ]                       ["t with 20 d.f", "t with 21 d.f", "z", "Both"]      

What is the critical value?                            [ Select ]                       ["-1.7247", "1.645 and -1.645", "2.58", "1.645"]      

What is the Test Statistic Value?                            [ Select ]                       ["-1", "-3.67", "-3.87", "3.67"]      

What is the P-value?                            [ Select ]                       ["0.5", "0.001<pvalue<0.01", "0.001", "0.0005<pvalue<0.005"]      

What is the conclusion of the test?                            [ Select ]                       ["Test is Significantly Sufficient", "Test is Incomplete", "Test is Insignificant", "Test is Significant"]      

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Answer 1

Hence, there is enough evidence to conclude that the stopping distance for a car traveling at 55 mph is less than the stated 130 ft at 5% level of significance.