A car dealership claims that its average service time is less than 7 hours on weekdays....

A car dealership claims that its average service time is less than 7 hours on weekdays. A random sample of 16 service times was recorded and yielded the statistics x ̅=6.75 hours and s= 1.62 hours. Assume service times are normally distributed, is there enough evidence to support the dealership’s claim at 5% significance level? 10 marks (Please show every step for full marks)

Hypotheses:

Rejection Region:

Test Statistic:

Decision/Conclusion:

Solutions

Expert Solution

This is the left tailed test .

The null and alternative hypothesis is

H₀ : = 7

H_a : < 7

Test statistic = t

= ( - ) / s / n

= (6.75 - 7) / 1.62 / 16

= -0.617

Test statistic = -0.617

df = 15

P-value = 0.2732

= 0.05

P-value >

Fail to reject the null hypothesis .

There is insufficient evidence to support the dealership’s claim at 5% significance level .

orchestra answered 1 year ago

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