A manufacturer of cordless electric shavers sampled 13 from a day's production and found the mean time of continuous usage without recharging to be 410 minutes with a sample standard deviation of 30 minutes.We can assume that times are normally distributed.We wish to test if the true mean operating time without recharging is more than 400 minutes.The correct null and alternative hypotheses are ________________________ . A)H_{0 :}µ = 400; H_A : µ 400 C)H_{0 :}µ 400; H_A : µ = 400 D)H_{0 :}µ

Question

A manufacturer of cordless electric shavers sampled 13 from a day's production and found the mean time of continuous usage without recharging to be 410 minutes with a sample standard deviation of 30 minutes.We can assume that times are normally distributed.We wish to test if the true mean operating time without recharging is more than 400 minutes.The correct null and alternative hypotheses are ________________________ . A)H_{0 :}µ = 400; H_A : µ < 400 B)H_{0 :}µ = 400; H_A : µ > 400 C)H_{0 :}µ > 400; H_A : µ = 400 D)H_{0 :}µ < 400; H_A : µ = 400 E)H_{0 :}µ = 400; H_A : µ ≠ 400

Quizplus · Accepted Answer

The null hypothesis (H0) is a statement of no effect or no difference, and it is what we seek evidence against. Here, it is that the true mean operating time is 400 minutes (µ = 400). The alternative hypothesis (Ha) represents the outcome the test is trying to support, in this case, that the true mean operating time is more than 400 minutes (µ > 400).

A Manufacturer of Cordless Electric Shavers Sampled 13 from a Day's