The number of chocolate chips in an 18 ounce bag of chocolat

The number of chocolate chips in an 18 ounce bag of chocolate chips os approxiamately normally distributed with a mean of 1252 chipos and standard deviation 129 chips.

(a) What is the probability that a randomly selected bag contains between 1000 and 1500 chocolate chips, inclusive?

(b) What is the probability that a randomly selected bag contains fewer 1050 chocolate chips?

(c) What proportion of bags contains more than 1175 chocolate chips?

(d) What is the percentile rank of a bag that contains 1475 chocolate chips?

Round to four decimal places as needed.

Solution

The number of chocolate chips in an 18 ounce bag of chocolate chips os approxiamately normally distributed with a mean of 1252 chipos and standard deviation 129 chips.

Z value for 1000, (1000-1252)/129 = -1.95

Z value for 1500, (1500-1252)/129 = 1.92

P( 1000<X<1500) = P( -1.95<z<1.92) =

P( z <1.92)