# Probability distribution - normal curve 68-95-99 rules

A software company finds that the average number of errors in its software per 1000 lines of code is 4 with standard deviation equal to 0.5. Use the 68-95-99.7 rule to calculate the following values:

a)Almost all (99.7%) 1000 lines of code contain a number of errors that varies in what range of values?

b)The percentage of samples of 1000 lines of code that contain between 3 and 5 errors.

c)The percentage of samples of 1000 lines of code that contain less than 2.5 errors.

d)The 2.5th percentile of the distribution of the number of errors per 1000 lines of code.

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#### Solution Preview

A software company finds that the average number of errors in its software per 1000 lines of code is 4 with standard deviation equal to 0.5. Use the 68-95-99.7 rule to calculate the following values:

a)Almost all (99.7%) 1000 lines of code contain a number of errors that varies in what range of values?

99.7% values will lie within +/- 3 standard deviations of ...

#### Solution Summary

Illustrates how to calculate the probabilities for a normal curve