Find the mean and standard deviation of the DRIVE variable by using =AVERAGE (A2

Question

Find the mean and standard deviation of the DRIVE variable by using =AVERAGE (A2:A36) and =STDEV(A:2 A:36) Assuming that this variable is normally distributed, what percentage of data would you predict would be less than 40 miles? This would be based on the calculated probability. Use the formula=NORM.DIST (40, mean, stdev, TRUE). Now determine the percentage of data points in the dataset that fall within the range. To find the actual percentage in the dataset, sort the DRIVE variable and count how many of the data points are less than 40 out of the total 35 data points. This is the actual percentage. How does this compare with your prediction?

mean___________

Standard deviation________

Predicted percentage_______

actual percentage________

Comparison____________

Drive/miles

54,78,71,94,80,36,36,6,28,55,36,6,42,33,36,80,63,40,4,25,80,76,20,73,25,88,76,29,76,63,71,42,54,80,36.

Explanation / Answer

mean = 51.2 ( =AVERAGE(A2:A36) )

Standard deviation = 25.49948 ( =STDEV(A2:A36) )

Predicted percentage = 0.3302 ( =NORMDIST(40,51.2,25.49948,TRUE) )

Number of the data points are less than 40 out of the total 35 are 14 ( Excluding 40)

So actual percentage = 14 / 34 = 0.4

Comparison : actual percentage is greater than predicted percentage.

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