Answer: D. 0.306
Step-by-step explanation:
Assuming a normal distribution for the annual salary for intermediate level executives, the formula for normal distribution is expressed as
z = (x - u)/s
Where
x = annual salary for intermediate level executives
u = mean annual salary
s = standard deviation
From the information given,
u = $74000
s = $2500
We want to find the probability that the mean annual salary of the sample is between $71000 and $73500. It is expressed as
P(71000 lesser than or equal to x lesser than or equal to 73500)
For x = 71000,
z = (71000 - 74000)/2500 = - 1.2
Looking at the normal distribution table, the probability corresponding to the z score is 0.1151
For x = 73500,
z = (73500 - 74000)/2500 = - 0.2
Looking at the normal distribution table, the probability corresponding to the z score is 0.4207
P(71000 lesser than or equal to x lesser than or equal to 73500) is
0.4207 - 0.1151 = 0.306