math
posted by Sally .
If the population is bellshaped, then the interval that is 3 standard deviation away from the center contains what percent of data in the population?

.27 percent
http://www.math.csusb.edu/faculty/stanton/m262/normal_distribution/normal_distribution.html 
The mean length of the first 20 space shuttle flights was about 7 days, and
the standard deviation was about 2 days. On the basis of Chebychev’s
Theorem, at least how many of the flights lasted between 3 days and 11
days?