The number of pieces of popcorn in a large movie theatre popcorn bucket is normally distributed, with a mean of 1720 and a standard deviation of 20. Approximately what percentage of buckets contain between 1680 and 1760 pieces of popcorn?

Question

The number of pieces of popcorn in a large movie theatre popcorn bucket is normally distributed, with a mean of 1720 and a standard deviation of 20. Approximately what percentage of buckets contain between 1680 and 1760 pieces of popcorn?
a.approximately 68%
b.approximately 75%
c.approximately 95%
d.99.7%​

R_scott · Answer

approximately 95% of a normally distributed population ... lies within 2 s.d. of the mean

Reiny · Answer

Perfectly suited for David's applet http://davidmlane.com/normal.html

Jay · Answer

C. Approximately 95%