Statistics Question Empirical Rule!?
A company has a policy of retiring company cars; this policy looks at number of miles driven, purpose of trips, style of car and other features. The distribution of the number of months in service for the fleet of cars is bell-shaped and has a mean of 45 months and a standard deviation of 4 months. Using the empirical rule (as presented in the book), what is the approximate percentage of cars that remain in service between 49 and 53 months?
ans=_________?
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The measurements given are one (49) and two standard deviations (53) the right of the mean. Two standard deviations represent approximately 95 percent of the area under the normal curve. But these deviations are only on the positive side, so we must halve them to get the proper area.
95/2 = about 47.5 percent.
Also, we must subtract out 34 percent for the one standard deviation to the right of the mean in order to get the area between one and two standard deviations to the right of the mean.
47.5 - 34 = 13.5 percent <==answer.
properly, sixty 8 is two time-honored deviations from the advise, as is 80 seventy 4-3*2=sixty 8 seventy 4+3*2=80 The empirical rule states that sixty 8% of documents will fall interior of a million time-honored deviation of the advise, ninety 5% interior of two, and ninety 9.7% interior of three time-honored deviations. So, the respond is ninety 5%, and it is an approximation.