xmagedo wrote:
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 shown above is 10 and 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%
Mean = 10; SD=0.3
Range of values below 1 SD = Mean - 1 SD
Range = 10-0.3 to 10+0.3 = 10.30 to 9.70
9.4 , 9.9 , 9.9 , 9.9 , 10.0 , 10.2 , 10.2 , 10.5
Outside the range = 9.4 and 10.5 ; total 2/8Inside the range 9.9 , 9.9 , 9.9 , 10.0 , 10.2 , 10.2 ; total 6/8 6/8 = 0.75 or 75%
ANSWER IS D
_________________
Posting an answer without an explanation is "GOD COMPLEX". The world doesn't need any more gods. Please explain you answers properly.
FINAL GOODBYE :- 17th SEPTEMBER 2016. .. 16 March 2017 - I am back but for all purposes please consider me semi-retired.