In: Statistics and Probability
A sample of n = 36 observations is drawn from a normal population, with = 500 and = 42. Find P(500 < X̅ < 510).
| a. |
0.0764 |
|
| b. |
0.8756 |
|
| c. |
0.9236 |
|
| d. |
0.7556 |
|
| e. |
0.4236 |
Solution :
Given that ,
mean =
= 500
standard deviation =
= 42
n = 36

= 500

=
/
n= 42/
36=7
P(500<
<510
) = P[(500-500) /7 < (
-
) / 
< (510-500) /7 )]
= P(0 < Z <1.43 )
= P(Z < 1.43) - P(Z < 0)
Using z table
=0.9236-0.5
=0.4236