Download Section 7.3

7.3 NORMAL DISTRIBUTION
A standardized normal distribution is a normal distribution with a
mean of 0 and a standard deviation of 1.
If I know the area under the curve can I figure out the z-value it corresponds with? YES!!!!!
WORK BACKWARDS
1) If the probability of getting less than a certain z-value is 0.1190, what is the z-value?
2) If the probability of getting larger than a certain z-value is 0.0129, what is the z-value?
3) Find z, if the area under a standard normal curve
a. between z = 0 and z is 0.3485
b. to the right of z is 0.0307
c. to the left of z is 0.7324
d. between z = 1.84 and z is 0.127
7.3 NORMAL DISTRIBUTION
THE GENERAL NORMAL DISTRIBUTION
If we are given a normal distribution with a mean different from 0 and a standard deviation
different from 1, we can CONVERT this normal distribution into a standardized normal
distribution by converting each of its scores into standard scores.
USE THIS FORMULA TO CONVERT INTO STANDARD SCORES
z
x

, x    z
4) In a normal distribution   25 and   5 , what is the probability of obtaining a value
a. Between 21 and 28?
b. Greater than 30?
5) Find the percentile rank of a score of 20 in a normal distribution with   15 and   2.3 .
6) In the Key Club, heights of members are normally distributed with   63 in and   2 in .
a. If Mike is in the 90th percentile, find his height.
b. If George is in the 65th percentile, find his height.