In: Statistics and Probability
The original population is extremely large and has u=35 and o=8. A simple random sample of size n=49 is to be drawn.Let x be the mean of the sample. Find P(33<x<34)
Hint : u is population mean and o is standard deviation
Solution :
Given that,
mean = = 35
standard deviation = = 8
n = 49
= 35
= / n = 8 49 = 1.1428
P (33 < < 34 )
P ( 33 - 35 / 1.1428) < ( - / ) < ( 34 - 35 / 1.1428 )
P ( - 2 / 1.1428 < z < - 1 / 1.1428 )
P (-1.75 < z < - 0.87)
P ( z < - 0.87 ) - P ( z < -1.75)
Using z table
= 0.1922 - 0.0401
= 0.1521
Probability = 0.1521