The weights of ripe watermelons grown at Mr Smiths farm are

The weights of ripe watermelons grown at Mr. Smith\'s farm are normally distributed with a standard deviation of 2.9 lb. Find the mean weight of Mr. Smith?s ripe watermelons if only 8% weigh less than 17 lb. (Give your answer correct to one decimal place.) lb

Solution

P(X<17) =0.08

--> P((X-mean)/s <(17-mean)/2.9) =0.08

--> P(Z<(17-mean)/2.9) = 0.08

--> (17-mean)/2.9= -1.41 (from standard normal table)

--> 17-mean= -1.41*2.9 =-4.089

So mean= 17+4.089 =21.1