Make the drawing.
a. Remember that the mean = median in a normal distribution.
b. Since 68% score within one SD of the mean, 34% score above the mean and 34% score below. Since you are at +1 SD, add % below mean and the 34% between mean and +1 SD.
Use a similar process for answering the remaining problems.
Using the 68-95-99.7 rule:
Assume that a set of test scores is normally distributed with a mean of 100 and a standard deviation of 20. Use the 68-95-99.7 rule to find the following quantities:
Suggest you make a drawing and label first…Drawings need not be included in response.
a. Percentage of scores less than 100
b. Relative frequency of scores less than 120
c. Percentage of scores less than 140
d. Percentage of scores less than 80
e. Relative frequency of scores less than 60
f. Percentage of scores greater than 120
1 answer
1 answer