Download Practice on the Empirical Rule and Normal Distribution I. In a Normal

Practice on the Empirical Rule and Normal Distribution
I. In a Normal distribution, what percent of the values lie…
1. below the mean? ____________
2. above the mean? ____________
3. within one standard deviation of the mean? ____________
4. within two standard deviations of the mean? ____________
5. within three standard deviations of the mean? ____________
II. 2000 freshmen at State University took a biology test. The scores were distributed Normally with a
mean of 70 and a standard deviation of 5.
6. Label the mean and three standard deviations from the mean.
7. What percentage of scores are between scores 65 and 75?
8. What percentage of scores are between scores 60 and 85?
9. What percentage of scores is less than a score of 55?
10. What percentage of scores is greater than a score of 80?
11. Approximately how many biology students scored between 60 and 70?
12. Approximately how many biology students scored between 55 and 60?
III. 1800 freshmen were admitted to GRU this fall. The scores on the SAT were distributed Normally with a
mean of 520 and a standard deviation of 90.
13. Label the mean and three standard deviations from the mean.
14. What percent of students scored between 340 and 700?
15. What percent of students scored between 430 and 700?
16. What percent of students scored below 430?
17. What percent of students scored above 700?
18. How many students would you expect scored below 520?
19. How many students would you expect scored above 610?
IV. Given the dotplot below, calculate the mean and standard deviation. Label  ,  , and -  on the dot plot. Use
these values to determine whether the distribution could be normal.
Histogram
Collection 1
20. mean = ______________________
6
21. standard deviation = _______________________
Count
5
4
22.    = ___________________
3
2
23.    = ___________________
1
44
46
48
data
50
52
24. What percent of the data is within one  of  ?
25. Does the distribution appear Normal?