# Normal Probability

A normal distribution has a mean of 50 and a standard deviation of 4.

a. Compute the probability of a value between 44.0 and 55.0.

b. Compute the probability of a value greater than 55.0.

c. Compute the probability of a value between 52.0 and 55.0.

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A normal population has a mean of 12.2 and a standard deviation of 2.5.

a. Compute the z value associated with 14.3.

b. What proportion of the population is between 12.2 and 14.3?

c. What proportion of the population is less than 10.0?

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Fix-It Copiers advertises a mean time of 100 minutes for office calls with a standard deviation of 25 minutes. What percentage of calls are completed:

a. between 100 and 120 minutes?

b. in less than 120 minutes?

c. in less than 60 minutes?

d. between 120 and 150 minutes?

e. between 60 and 120 minutes?

f. Twenty percent of their jobs take more than how much time?

https://brainmass.com/statistics/probability/to-determine-probabilities-of-normal-distribution-85184

#### Solution Summary

The expert determines probabilities of normal distribution.