answer the following questionshow your all calculations 1The

answer the following question:show your all calculations

1.The distribution of lifetime mileages for an economy tire is symmetric and bell-shaped. According to the empirical rule, approximately 95% of the economy tires have a lifetime mileage between 60,000 miles and 68,000 miles. Use this information to fill in the missing values for this question and the next.

The mean lifetime mileage for an economy tire is __________ miles.

2.The distribution of lifetime mileages for an economy tire is symmetric and bell-shaped. According to the empirical rule, approximately 95% of the economy tires have a lifetime mileage between 60,000 miles and 68,000 miles. Use this information to fill in the missing values for this question and the next.

The standard deviation for lifetime mileage for an economy tire is _________ miles.

Solution

(1) mean=(60000+68000)/2 = 64000

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(2) mean - 2*standard deviation =60000

--> 64000 -2*standard deviation =60000

--> 2*standard deviation = 64000-60000=4000

So standard deviation = 4000/2= 2000