Question

In: Statistics and Probability

A tire manufacturer has been producing tires with an average life expectancy of 26,000 miles. Now...

A tire manufacturer has been producing tires with an average life expectancy of 26,000 miles. Now the company is advertising that its new tires' life expectancy has increased. In order to test the legitimacy of the advertising campaign, an independent testing agency tested a sample of 6 of their tires and has provided the following data. Ho: m < 26 Ha: m > 26 Life Expectancy (In Thousands of Miles) 28 27 25 28 29 25

At 99% confidence, what is the critical value?

Test to determine whether or not the tire company is using legitimate advertising. hypothesis

Solutions

Expert Solution

Solution-

LET BE THE AVERAGE LIFE EXPECTANCY OF TIRES. WE CLAIM THAT THE LIFE EXPECTANCY HAS INCREASED. THE HYPOTHESIS WE FRAME IS,

(in thousands)

AS THE POPULATION SD IS UNKNOWN, WE PERFORM A ONE SAMPLE-T TEST AT 0.01 SIGNIFICANCE LEVEL AND USE MINITAB-16 FOR CALCULATION.

STEPS- ENTER THE DATA> STAT> BASIC STATISTICS> ONE SAMPLE-T> SELECT THE SAMPLE> SET THE HYPOTHESISED MEAN AS 26> UNDER 'OPTIONS', SET THE CONFIDENCE LEVEL AS 99.0 AND ALTERNATE AS 'GREATER THAN'> OK.

AT 99% SIGNIFICANCE, THE CRITICAL VALUE IS 3.365

THE COMPUTED TEST STATISTIC IS T=1.46

AS T<3.365, WE FAIL TO REJECT THE NULL HYPOTHESIS. SO WE CAN CONCLUDE THAT THE EXPECTANCY OF TIRES HAVE NOT INCREASED AND THE COMPANY IS NOT USING A LEGITIMATE ADVERTISING.

****IN CASE OF DOUBT, COMMENT BELOW. ALSO LIKE THE SOLUTION IF POSSIBLE.


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