Answer:
Step-by-step explanation:
Null hypothesis: u = 39.8
Alternative: u =/ 39.8
Using a one sample z test: the formula is
z = x-u / (sd/√n)
Where x = 33.1 u = 39.8, sd= 16.2 and n = 38
Thus we have:
z = 33.1-39.8 / (16.2/√38)
z = -6.7 / (16.2/6.1644)
z = -6.7/ 2.6280
z= -2.5495
To be able to arrive at a conclusion, we have to find the p value, the p value at a 0.1 significance level for a two tailed test is 0.0108. This is way less than 0.1 thus we will reject the null and conclude that there has been a change (either way) in the average number of e-mails received per day per employee. Yes, the new policy had an effect.