Suppose a normal distribution has a mean of 79 and a standard deviation of 7. What is P (x > or = to 86) ?

P (X > = 86) = P (Z > = 1) = 0.1587 from the Z-scores table

Step-by-step explanation:

Hopefully this time I will not make an algebraic mistake.

Ok

so mean u = 79, and standard dev = s = 7

We want P (X > = 86)

Standardize:

P ((X - u) / s > = (86 - 79) / 7) = P (Z > = 1) = 0.1587 from the Z-scores table