Question

This is a word problem. "We know that for certain workers the mean wage is $5/hr with a standard deviation of $.50. We need to find out if a worker is chosen at random what is the probability that the workers' wage is between $4.50 and $5.50? Assume a normal distribution of wages." I know that 68% of the workers' wages are between the two amounts but how do I determine the probability??

Answer 1

If you know that 68% of the wages are between the standard deviation range, which is true for a normal distribution, then you already have the answer. That IS the probability.

Answer 2

Here is a nice little applet that will illustrate what drwls said
http://davidmlane.com/hyperstat/z_table.html

In the mean enter 5
in the Sd enter .5

click on "between" and will in 4.5 and 5.5


the shaded area is both the percentage and the probability