SOLUTION: 3a. If the standard deviation of a group of students’ test scores was calculated as 6.5 points and the mean of their distribution of scores was 75.5%, how many standard deviations

Algebra ->  Probability-and-statistics -> SOLUTION: 3a. If the standard deviation of a group of students’ test scores was calculated as 6.5 points and the mean of their distribution of scores was 75.5%, how many standard deviations       Log On


   

Question 46743: 3a. If the standard deviation of a group of students’ test scores was calculated as 6.5 points and the mean of their distribution of scores was 75.5%, how many standard deviations was a student’s score who scored 80%?
3b. Using the data above in question 3a, calculate the student’s standardized Z score. Use the formula:
z =X-mean/s

Answer by AnlytcPhil(1806) About Me  (Show Source):
You can put this solution on YOUR website!
3a. If the standard deviation of a group of students’ test 
scores was calculated as 6.5 points and the mean of their 
distribution of scores was 75.5%, how many standard 
deviations was a student’s score who scored 80%?

3b.  Using the data above in question 3a, calculate the 
student’s standardized Z score.  Use the formula:
                  _
		z = (x - x)/s 
                     _ 
Just plug in x = 80, x = 75.5 and s = 6.5

                z = (80 - 75.5)/6.5

                z = 0.6923076923

which means that the student scored about 0.7 of a 
standard deviation above (since it's positive) the mean.

Edwin