1. A mechanic sells a brand of automobile tire that has a life expectancy that is normallydistributed, with a mean life of 24,000miles and a standard deviation of 2500miles. He wants to give a guarantee for free replacement of tires thatdon't wear well. How should he word his guarantee if he is willing to replace approximately10% of thetires?Tires that wear out by ___ miles will be replaced free of charge.

2.Find the probability and interpret the results. If convenient, use technology to find the probability. The population mean annual salary for environmental compliance specialists is about $61,500. A random sample of 37 specialists is drawn from this population. What is the probability that the mean salary of the sample is less than $59,000? Assume sigma equals=$5,500.

a)The probability that the mean salary of the sample is less than $59,000 is

b)Interpret the results.

3.In a random sample of 35 refrigerators, the mean repair cost was $112.00 and the population standard deviation is $18.80. Construct a 95% confidence interval for the population mean repair cost. Interpret the results

a)The 95% confidence interval is left parenthesis nothing comma nothing right parenthesis .

b)Interpret your results

4.In a survey of women in a certain country (ages 2029), the mean height was 62.96 inches with a standard deviation of 2.94 inches. Answer the following questions about the specified normal distribution.(a) What height represents the 85th percentile? (b) What height represents the first quartile?

5.You are given the sample mean and the population standard deviation. Use this information to construct the 90% and 95% confidence intervals for the population mean. Which interval is wider? If convenient, use technology to construct the confidence intervals. A random sample of 45 gas grills has a mean price of $644.60 Assume the population standard deviation is $56.40.

a)The90% confidence interval is b) 95%