Question

The actual weights of bag of pet food are normally distributed.The mean of the weights is 50.0 lb,with a standard deviation of 0.2 lb.

B) In a group of 250 bags,how many would you expect to weigh more than 50.4 lb?

Answer 1

That would be 2 sigma or more above the mean.
2.5% is 2 sigma or more above the mean
2.5% is 2 sigma or more below the mean
95% is between the 2 sigma points (49.6 to 50.4 in this case)
It's something worth remembering