posted by brenduh on .
The mean of a normal distribution is 400 pounds. The standard deviation is 10 pounds. What is the area between 415 pounds and the mean of 400 pounds? The area between the mean and 395?
Hmmm. Area? or do you mean the probability? The area under a probability density function is area, so you have a probabliity density x deviation which equals probability. The entire area is 1.00 under the function.
See this applet:http://psych.colorado.edu/~mcclella/java/normal/accurateNormal.html
The area under the curve indicates the probability. Use the Z-score to determine area.
Z = (x - μ )/SD, where x = score, μ = mean, and SD = standard deviation.
Use table in your statistics text called "areas under normal distribution" or the source indicated by bobpursley to get the area from the Z-score.
I hope this helps a little more. Thanks for asking.