Let x be a normally distributed random variable having mean = 30 and standard deviation

Let x be a normally distributed random variable having mean μ = 30 and standard deviation σ = 5. Find the z value for each of the following observed values of x:
a. x = 25
b. x = 15
c. x = 30
d. x = 40
e. x = 50
In each case, explain what the z value tells us about how the observed value of x compares to the mean, μ.