Suppose the weights of Golden Retrievers are normally distri
Suppose the weights of Golden Retrievers are normally distributed with a mean of 64 lbs and a standard deviation of 4 lbs.
a) What proportion of Golden Retriever weighs between 58 lbs and 70 lbs?
b) What proportion of Golden Retrievers weigh more than 72 pounds?
c) 80% of Golden Retrievers weigh more than __________
Solution
Suppose the weights of Golden Retrievers are normally distributed with a mean of 64 lbs and a standard deviation of 4 lbs.
Z value for 58, z = (58- 64)/4 =-1.5
Z value for 70, z = (70- 64)/4 =1.5
P( 58 <X<70)= P(-1.5<z<1.5) =
=p(z<1.5 ) - P(z < -1.5) = 0.9332 - 0.0668 =0.8664
Z value for 72, z = (72- 64)/4 = 2
P( x>72) = P(z>2) = 0.0228
c) 80% of Golden Retrievers weigh more than __________
z value for more than 80% values = -0.842
The required value = 64 - 0.842*4 = 60.632
