In: Statistics and Probability
2] Let x be a continuous random variable that has a normal distribution with μ = 48 and σ = 8 . Assuming n N ≤ 0.05 , find the probability that the sample mean, x ¯ , for a random sample of 16 taken from this population will be between 49.64 and 52.60 .
Round your answer to four decimal places.
Solution :
Given that,
mean =
= 48
standard deviation =
= 8
n = 16
=
= 48
=
/
n = 8 /
16 = 2
P(49.64 <
< 52.60)
= P[(49.64 - 48) / 2 < (
-
)
/
< (52.60 - 48) / 2 )]
= P(0.82 < Z < 2.30)
= P(Z < 2.30) - P(Z < 0.82)
Using z table,
= 0.9893 - 0.7939
= 0.1954