In: Statistics and Probability
Solution :
Given that ,
= 70
= 20
A sample of size n = 16 is taken from this population.
Let
be the mean of sample.
The sampling distribution of the
is approximately normal with
Mean
=
= 70
SD
=
= 20/
16
= 5
Find, P(66 <
< 71)
= P(
< 71) - P(
< 66)
= P[(
-
)/
< (71 - 70)/5] - P[(
-
)/
< (66 - 70)/5]
= P[Z < 0.2] - P[Z < -0.8]
= 0.5793 - 0.2119 .........(use z table)
= 0.3674
P(66 <
< 71) = 0.3674