gre math prob of a sample
posted by luckybee on .
sample standard deviation = 3
sample mean = 68
n=30
what is the probability that one student selected at random from the sample will have a height within one sample standard deviation of the sample mean?
a. 1.00
b. 0.73
c. 0.57
d. 0.23

mean ± 1 SD = 68.26%
This is true for any normal distribution. Is there something you are not telling me? 
There is a picture of a histogram. the numbers on the xaxis are: 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, and 76. the numbers on the taxis are: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. there are additional symbols: sigma x =2100, sigma x^2=142540, and Sx=3