Answer:
99.38%
Step-by-step explanation:
We have that the mean (m) is equal to 124, the standard deviation (sd) 6.4 and the sample size (n) = 64
They ask us for P (x <126)
For this, the first thing is to calculate z, which is given by the following equation:
z = (x - m) / (sd / (n ^ 1/2))
We have all these values, replacing we have:
z = (126 - 124) / (6.4 / (64 ^ 1/2))
z = 2.5
With the normal distribution table (attached), we have that at that value, the probability is:
P (z <2.5) = 0.9938
The probability is 99.38%
