Q:

Statistics from Cornell's Northeast Regional Climate Center indicate that Ithaca, NY, gets an average of 35.4 inches of rain each year, with a standard deviation of 4.2 inches.During what percentage of years does Ithaca get more than 30 inches of rain?a. approximately 10.03%b. approximately 10.95%c. approximately 90.07%d. approximately 5.82e. approximately 94.18%

Accepted Solution

A:
Answer:c. approximately 90.07%Step-by-step explanation:We need to calculate z-statistic of 30 inches of rain in the normal distribution with an average of 35.4 inches of rain each year, and a standard deviation of 4.2 inches.z score can be calculated using the formula z=[tex]\frac{X-M}{s}[/tex] where X =30 inches of rainM is the average rain in inches (35.4)s is the standard deviation (4.2)using the numbers we get z=[tex]\frac{30-35.4}{4.2}[/tex] β‰ˆ βˆ’1,286Then percentage of years does Ithaca get more than 30 inches of rain is P(z>-1.286) =1- P(z<-1.286)=1-0.0993 β‰ˆ0.9007 or 90.7%