3. Company A claims that its light bulbs are superior to those from company B.A study shows that a sample of 10 bulbs fr

[answerhappygod]

3 Company A Claims That Its Light Bulbs Are Superior To Those From Company B A Study Shows That A Sample Of 10 Bulbs Fr 1 (40.15 KiB) Viewed 33 times

3. Company A claims that its light bulbs are superior to those from company B.A study shows that a sample of 10 bulbs from company A has a mean lifetime 647 hours of continuous use with a standard deviation of 27 hours, while a sample of 8 bulbs from company B had a mean life time of 638 hours of continuous use with a standard deviation of 31 hours. Calculate the 90% confidence interval for the difference of the two means. (5 points) 4. At a large university, the mean age of students is 22.3 years, and standard deviation is 4 years. Random samples of 64 students are drawn. (a) What type of distribution is the sampling distribution of mean and why? (b) What is the probability that the average age of these 64 students is greater than 23 years? (5 points)