Z = (score-mean)/SD
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability of the Z score.
ľ Bob takes an online IQ test and finds that his IQ according to the test is 134. Assuming that the mean IQ is 100, the standard deviation is 15, and the distribution of IQ scores is normal, what proportion of the population would score higher than Bob? Lower than Bob?
2 answers
The mean age at which men in the United States marry for the first time follows the normal distribution with a mean of 24.4 years. The standard deviation of the distribution is 2.6 years.
For a random sample of 57 men, what is the likelihood that the age at which they were married for the first time is less than 24.9 years?
For a random sample of 57 men, what is the likelihood that the age at which they were married for the first time is less than 24.9 years?
1 answer