[For questions 8, 9, and 10] - The old Nokia 3310 battery lasts 31 hours on standby. Nokia produces a new Nokia that is advertised to last longer than the Nokia 3310. This was tested by charging the new Nokia and letting it die 80 times - the average time for the battery to die was 33.5 hours, with a standard deviation of 4 hours. How confident can we be that this new phone lasts longer than the Nokia 3310? 99% O >99% 97.5% 95%

Please answer the remaining questions

Please answer a-d

Two chemical companies can supply a raw material. The concentration of a particular element in this material is important. The mean concentration for both suppliers is the same, but you suspect that the variability in concentration may differ for the two companies. The standard deviation of concentration in a random sample of n₁ = 10 batches produced by company 1 is s₁ = 4.7 grams per liter, and for company 2, a random sample of n₂ = 16 batches yield s₂ = 5.8 grams per liter. Is there sufficient evidence to conclude that the two populations variances differ? Use a = 0.05. a. Because 0.321 < 0.657 <3.77, fail to reject the null hypothesis b. Because 0.265 < 0.657 <3.12, fail to reject the null hypothesis c. Because 0.386 < 0.657 <3.01, fail to reject the null hypothesis d. None among the choices

Solve question 9, Part A, Part B and Part C only.

Solve question #9 for part D only.