In a particular city the average annual salary for secretari

In a particular city, the average annual salary for secretaries is $28,000. A sample of 40 secretaries from Company A shows an average annual salary of $23,500 with a population standard deviation of $4,000. Secretaries at Company A claim they are paid less than the city average. What is the test value for this claim?

A) -7.12

B) -1.13

C) 1.13

D) 7.12

Solution

              
Getting the test statistic, as              
              
X = sample mean =    23500          
uo = hypothesized mean =    28000          
n = sample size =    40          
s = standard deviation =    4000          
              
Thus, z = (X - uo) * sqrt(n) / s =    -7.115124735 = -7.12 [ANSWER, A]