Question

A manufacturer daims that the mean lifetime, H, of its light bulbs is 43 months. The standard deviation of these lifetimes is 8 months. Seventy bulbs are selected at random, and their mean lifetime is found to be 44 months. Can we conclude, at the 0.01 level of significance, that the mean lifetime of light bulbs made by this manufacturer differs from 43 months? Perform a two-tailed test. Then fill in the table below. Carry your intermediate computations to at least three decimal places, and round your responses as specified in the table. р o р The nullwypothesis: x s The alternative hypothesis: D- The type of test statistici (Choose one) DD x ? The value of the test statistics (Round to at least three 0 decimal places.) The two critical values at the 0.01 level of significance and D (Round to at least three cecimal places) Can we condude that the mean lifetime of it bulbs made by this manufacturer differs from 43 months O No

Answer 1

Answer? given M = 43 S: 8 mean n= 70 signife cance level x= 0.01 The null hypothesis Ho: M= 43 The alternative hypothesis H, : " !=43 The type of test statistic: Z statistic two tasted) The value of the test statistic z = X-M lun 44-43 86. 0.9562 1.046 001 level of The two coitical values at the significance = -2.516, 2.576

can we conclude that the mean lifetime of light bulbe made by this manufacture differs from 43 months fail to reject How We No NOTE: Please likecececce