A group of students weighs 500 us pennies. they find that the pennies have normally distributed weights with a mean of 3.1g and a standard deviation 0.14g.
a) what percentage of pennies will weigh between 2.8 and 3.3g
b) what percentage of pennies will weigh between 2.11 and 3.5g
c) what percentage of pennies will weigh less than 2.96g
d) what percentage will weigh more than 3.4g