A professional employee in a large corporation receives an a

A professional employee in a large corporation receives an average of ? = 42.4 e-mails per day. Most of these e-mails are from other employees in the company. Because of the large number of e-mails, employees find themselves distracted and are unable to concentrate when they return to their tasks. In an effort to reduce distraction caused by such interruptions, one company established a priority list that all employees were to use before sending an e-mail. One month after the new priority list was put into place, a random sample of 30 employees showed that they were receiving an average of x = 33.6 e-mails per day. The computer server through which the e-mails are routed showed that s = 19.4. Has the new policy had any effect? Use a 5% level of significance to test the claim that there has been a change (either way) in the average number of e-mails received per day per employee. What is the value of the test statistic?

Select one:

a. -0.083

b. 0.454

c. -0.454

d. 0.083

e. -2.485

Solution

H0:mu = 42.4

Ha:mu != 42.4

test statistics=(33.6-42.4)/(19.4/sqrt30)=-2.4845

critical values=+/-2.045

as test statistics falls outside interval we can reject H0

so data significantly support  claim that there has been a change (either way) in the average number of e-mails received per day per employee.