The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is ap
ID: 3292935 • Letter: T
Question
The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is approximately normally distributed with mean
1252
and standard deviation
129
chips.
(a) What is the probability that a randomly selected bag contains between
1000
and
1400
chocolate chips?
(b) What is the probability that a randomly selected bag contains fewer than
1100
chocolate chips?
(c) What proportion of bags contains more than
1225
chocolate chips?
(d) What is the percentile rank of a bag that contains
1050
chocolate chips?
Explanation / Answer
chips.
Part-a
P(1000<X<1400)= 0.8490
Using excel function
=NORMDIST(1400,1252,129,TRUE)- NORMDIST(1000,1252,129,TRUE)
Part-b
P(X<1100)=0.1193
Using excel function
=NORMDIST(1100,1252,129,TRUE)
Part-c
P(X>1225)= 0.5829
Using excel function
=1-NORMDIST(1225,1252,129,TRUE)
Part-d
P(X<1050)= 0.0587
Using excel function
=NORMDIST(1050,1252,129,TRUE)
So percentile ie 5.87%