Standardise the data and find the value using the normal distribution table.
In your case
kitchen appliances don't last forever. The lifespan of all microwave ovens sold in the united states is approximately normally distributed with a mean of 9 years and a standard deviation of 2.5 years. what percentage of the ovens last more than 10 years?
a. 11.5%
b. 34.5%
c. 65.5%
d. 69%
e. 84.5%