This question is from the GMAT Prep test. I didn't understand what "within 1 standard deviation of the mean" stands for.
Q. 9.4 , 9.9 , 9.9 , 9.9 , 10.0 , 10.2 , 10.2 , 10.5
The mean and the standard deviation of the 8 numbers is 10 & 0.3 respectively. What percent of the 8 numbers are within 1 standard deviation of the mean?
a. 90%
b. 85%
c. 80%
d. 75%
e. 70%
Q. 9.4 , 9.9 , 9.9 , 9.9 , 10.0 , 10.2 , 10.2 , 10.5
The mean and the standard deviation of the 8 numbers is 10 & 0.3 respectively. What percent of the 8 numbers are within 1 standard deviation of the mean?
a. 90%
b. 85%
c. 80%
d. 75%
e. 70%
