Answer:
solved
Step-by-step explanation:
Mean = 12
SD = 2
Answer to part 2) Less than 7 months
P(x < 7)
P(x < 7) = P(z < (7-12)/2) = P(z < -2.5)
This probability can be obtained by referring to the Z table
Thus P(x < 7) = 0.0062
1) Between 7 and 12 months
P(7 < x < 12) = P( x< 12) - P(x < 7)
We have P(x < 12) = 0 ......[because mean = 12]
and P(x < 7) = 0.0062 ...[this we got is part a]
Thus on plugging these values we get
P( 7 < x < 12) = 0.5 - 0.0062 = 0.4938
Thus P(7 < x < 12) = 0.4938
3
Answer:
Q.1. 0.4938
Q.2. 0.0062
Q.3. 0.1587
Step-by-step explanation:
Data
In the figure attached, the standard normal distribution table is shown.
Z = (x - μ)/σ
Q.1.
if x = 7, then Z = (7 - 12)/2 = -2.5
if x = 12, then Z = (12 - 12)/2 = 0
We want to find:
P(-2.5 < Z < 0) = P(Z < 0) - P(Z < -2.5) = 0.5 - 0.0062 = 0.4938
Q.2.
We want to find:
P(Z < -2.5) = 0.0062
Q.3.
if x = 5, then Z = (5 - 12)/2 = -3.5
if x = 10, then Z = (10 - 12)/2 = -1
We want to find:
P(-3.5 < Z < -1) = P(Z < -1) - P(Z < -3.5) = 0.1587 - 0 = 0.1587
