1.Apartment washing machines have become popular in the last years and Whirlpool would like to estimate the average life of its new line of apartment washing machines, in terms of how many washes it lasts. Determine the sample size needed to construct a 99% confidence interval with a margin of error equal to 2,000 washes. Assume the standard deviation for the machine life of this particular brand is 8,000 washes.

2.Dr. Paul Markowsky is responsible for the vaccine distribution in his area. He has 280 patients to receive the vaccine and will distribute a survey to them to ascertain their satisfaction with his effort. A random sample of 24 patients had an average satisfaction rating of 8.4 on a scale of 1-10. The sample standard deviation was 1.9.

a. Construct a 90% confidence to estimate the average satisfaction score for his practice.

3.A random sample of 40 taxpayers who work from home and with adjusted gross incomes of between $100,000 and $200,000 was drawn. These taxpayers claimed an average of $9,922 in home office expenses for the year. Assume the population standard deviation for these deductions was $2,400. Construct confidence intervals to estimate the average deduction for the population with the following levels of significance.

a. 2%

b. 5%

10%