The Rocky Mountain district sales manager of Rath Publishing Inc., a college tex

Question

The Rocky Mountain district sales manager of Rath Publishing Inc., a college textbook publishing company, claims that the sales representatives make an average of 37 sales calls per week on professors. Several reps say that this estimate is too low. To investigate, a random sample of 43 sales representatives reveals that the mean number of calls made last week was 39. The standard deviation of the sample is 2.4 calls. Using the 0.025 significance level, can we conclude that the mean number of calls per salesperson per week is more than 37?

H0 : 37 H1 : > 37

1. Compute the value of the test statistic. (Round your answer to 3 decimal places.)

Value of the test statistic

2. What is your decision regarding H0?

Reject or Accept H0? The mean number of calls is greater or less than 37 per week ?

Explanation / Answer

1.

Formulating the null and alternative hypotheses,              
              
Ho:   u   <=   37  
Ha:    u   >   37  
              
As we can see, this is a    right   tailed test.      
              
              
Getting the test statistic, as              
              
X = sample mean =    39          
uo = hypothesized mean =    37          
n = sample size =    43          
s = standard deviation =    2.4          
              
Thus, z = (X - uo) * sqrt(n) / s =    5.464532104 [ANSWER]

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2.          

Thus, getting the critical z, as alpha =    0.025   ,      
alpha =    0.025          
zcrit =    +   1.959963985      

As z > 1.96, we REJECT HO. [ANSWER]

There is no significant evidence that the true mean number of calls is greater than 37 per week. [ANSWER]

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