Question

A trucking company determined that the distance traveled per truck per year is normally​ distributed, with a mean of 60 thousand miles and a standard deviation of 10 thousand miles. Complete parts​ (a) through​ (d) below.

a. What proportion of trucks can be expected to travel between 48 and 60 thousand miles in a​ year?

b. What percentage of trucks can be expected to travel either less than 40 or more than 75 thousand miles in a​ year?

c. How many miles will be traveled by at least 85​% of the​ trucks?

d. What are your answers to parts​ (a) through​ (c) if the standard deviation is 8 thousand​ miles? I

f the standard deviation is 8 thousand​ miles, the proportion of trucks that can be expected to travel between 48 and 60 thousand miles in a year is . ​(Round to four decimal places as​ needed.)

If the standard deviation is 8 thousand​ miles, the percentage of trucks that can be expected to travel either less than 40 or more than 75 thousand miles in a year is . ​(Round to two decimal places as​ needed.)

If the standard deviation is 8 thousand​ miles, the number of miles that will be traveled by at least 85​% of the trucks is . ​(Round to the nearest mile as​ needed.)

Answer 1