The quality-control manager at a compact fluorescent light bulb (cfl) factory needs to determine whether the mean life of a large shipment of cfls is equal to 7 comma 454 hours. the population standard deviation is 1 comma 080 hours. a random sample of 81 light bulbs indicates a sample mean life of 7 comma 154 hours.

a. at the 0.05 level of significance, is there evidence that the mean life is different from 7 comma 454 hours question mark

Are there other options? BEcause the information you provided, you would NOT be able to say that the mean is different than 7,454 because the sample is within 1 standard deviation from the proposed mean.

hi : ) i found this so i hope this !

"we first find value of tax in dollars.

the difference between the two prices   is: 23. 54 - 22 = 1.54

therefore the sales tax in dollars is 1.54

the tax % will be   (amount of tax / original cost price ) × 100

(1.54 / 22) × 100  → (0.07) × 100 =   7

so the tax rate is 7%

we can double check the answer.

7 % of 22   → (7/100) × 22 → 0.07 × 22 = 1.54

22 + 1.54 = 23.54"

answer; be sure that the information on file is correct;