Answer:
The probability of his score being between 135 and 167 is 0.8151 or (0.8151*100=81.51%)
Step-by-step explanation:
Given that:
Mean = μ = 150
SD = σ = 12
Let x1 be the first data point and x2 the second data point
We have to find the z-scores for both data points
x1 = 135
x2 = 167
So,
![z_1 = \frac{x_1-mean}{SD}\\= \frac{135-150}{12}\\=\frac{-15}{12}\\=-1.25](https://tex.z-dn.net/?f=z_1%20%3D%20%5Cfrac%7Bx_1-mean%7D%7BSD%7D%5C%5C%3D%20%5Cfrac%7B135-150%7D%7B12%7D%5C%5C%3D%5Cfrac%7B-15%7D%7B12%7D%5C%5C%3D-1.25)
And
![z_2 = \frac{x_2-mean}{SD}\\z_2 =\frac{167-150}{12}\\=\frac{17}{12}\\= {1.416}](https://tex.z-dn.net/?f=z_2%20%3D%20%5Cfrac%7Bx_2-mean%7D%7BSD%7D%5C%5Cz_2%20%3D%5Cfrac%7B167-150%7D%7B12%7D%5C%5C%3D%5Cfrac%7B17%7D%7B12%7D%5C%5C%3D%20%7B1.416%7D)
We have to find area to the left of both points then their difference to find the probability.
So,
Area to the left of z1 = 0.1056
Area to the left of z2 = 0.9207
Probability to score between 135 and 167 = z2-z1 = 0.9027-0.1056 = 0.8151
Hence,
The probability of his score being between 135 and 167 is 0.8151 or (0.8151*100=81.51%)