We have here as as
, then the values are.
s=8.7
For the resulting of the test by the teacher he had,
With all of this dates to make the comparition we use the formula for Z values, that is
We know moreover that = 0.052.
To find we need to find
Searching in the table of Normal Distribution for Z, and making the lecture we find that z_{critic} is, 1.95.
