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In a sample of 55 business trips taken by employees in the HR department, a comp

ID: 3153994 • Letter: I

Question

In a sample of 55 business trips taken by employees in the HR department, a company finds that the average amount spent for the trips was $1,413 with a standard deviation of $443. In a sample of 81 trips taken by the employees in the sales department is $1,617 with a standard deviation of $534. When testing the hypothesis (at the 5% level of significance) that the average amount spent on trips taken by the sales department are higher than those taken by the HR department what is the test statistic? (please round your answer to 2 decimal places)

Explanation / Answer

Formulating the null and alternative hypotheses,              
              
Ho:   u1 - u2   >=   0  
Ha:   u1 - u2   <   0  
At level of significance =    0.05          
As we can see, this is a    left   tailed test.      
Calculating the means of each group,              
              
X1 =    1413          
X2 =    1617          
              
Calculating the standard deviations of each group,              
              
s1 =    443          
s2 =    534          
              
Thus, the standard error of their difference is, by using sD = sqrt(s1^2/n1 + s2^2/n2):              
              
n1 = sample size of group 1 =    55          
n2 = sample size of group 2 =    81          

Also, sD =    84.19387199          
              
Thus, the t statistic will be              
              
t = [X1 - X2 - uD]/sD =    -2.422979193 [ANSWER]

[If you are looking for a positive t value, then disregard the negative sign.

The answer would be t = 2.42. [ANSWER] ]

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