Standard Deviation and Normal Distribution Worksheet

**Page 3**

21.

The average age of the employees in an organization is 34 years. Assume the variable is normally distributed and the standard deviation is 4. If 25 employees are selected at random, then find the probability that the sample mean age of the employees is less than 35 years.

a. | 89.44% | ||

b. | 39.44% | ||

c. | 10.56% | ||

d. | 60.56% |

Let

The standard deviation of the sample mean is

The problem is to find P(

= P(

[Convert

= P(

[Use the standard normal distribution table.]

The probability of sample mean age of the employees is less than 35 years is 89.44%.

Correct answer : (1)