Do you know the 68-95-99.7 rule? Approximately 68% of scores in normal distribution are within one standard deviation (34% on each side of the mean), 95% within 2 SD, and 99.7% within 3 SD.
Z = (score-mean)/SD
You can also find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion/probability related to the Z scores.
scores on a University exam are normally distributed with a mean of 68 and a standard deviation of 9. use the 68-95-99.7 rule to answer the following questions
1) what proportions of students score between a 59 to 77?
2) what proportions of students score between a 50 to 86?
3) what proportions of students score above a 86?
4) what proportions of students score below a 41?
5) what proportions of students score above a 59?
6) what must a student score on the exam to be in the bottom 2.5% of scores on the exam?
1 answer
1 answer