Answer:
a) 0.7486; b) 0.6518; c) No
Step-by-step explanation:
We use z scores to answer these questions. The formula for a z score is
Our mean, μ, is 44; our standard deviation, σ, is 1.5.
For part a,
We want P(X > 43):
z = (43-44)/1.5 = -1/1.5 = -0.67
Using a z table, we see that the area under the curve to the left of this is 0.2514. However, we want the area to the right; this means we subtract from 1:
1 - 0.2514 = 0.7486
For part b,
We want P(42 ≤ X ≤ 45):
z = (42-44)/1.5 = -2/1.5 = -1.3
z = (45-44)/1.5 = 1/1.5 = 0.67
Using a z table, the area under the curve to the left of z = -1.3 is 0.0968. The area under the curve to the left of z = 0.67 is 0.7486.
The area between them is 0.7486 - 0.0968 = 0.6518.
For part c,
A response of 35 has a z score of
z = (35-44)/1.5 = -9/1.5 = -6
This is 6 standard deviations below the mean. This is more than the amount required to make this an outlier, or an unlikely response.
