Your organization is considering two methods by which employees can perform a ta
ID: 3130604 • Letter: Y
Question
Your organization is considering two methods by which employees can perform a task. You want to identify the method that, on average, is the shortest. A random sample of 6 workers is selected. Each worker first uses one method and then uses the other so that each worker provides a pair of completion times. Test the hypothesis that the two methods have the same mean completion time.
Completion times (mins)
Worker
Method 1
Method 2
Difference
1
6
5.4
0.6
2
5
5.2
-0.2
3
7
6.5
0.5
4
6.2
5.9
0.3
5
6
6
0
6
6.4
5.8
0.6
Average
6.1
5.8
0.3
Explain how to get standard deviation Sd =0.335
Explain exactly how to get 0.335 (I need to know this only)
Completion times (mins)
Worker
Method 1
Method 2
Difference
1
6
5.4
0.6
2
5
5.2
-0.2
3
7
6.5
0.5
4
6.2
5.9
0.3
5
6
6
0
6
6.4
5.8
0.6
Average
6.1
5.8
0.3
Explanation / Answer
Thus std deviation of difference is 0.305 and not 0.335
It is calculated by taking difference as x and finding out
E(x-0.3)^2 as variance and square root as std dev
Worker Method 1 Method 2 Difference x-mu (x-mu)^2 1 6 5.4 0.6 0.3 0.09 2 5 5.2 -0.2 -0.5 0.25 3 7 6.5 0.5 0.2 0.04 4 6.2 5.9 0.3 0 0 5 6 6 0 -0.3 0.09 6 6.4 5.8 0.6 0.3 0.09 Average 6.1 5.8 0.3 0 0.093333 Variance 0.597216 0.420317 0.305505 0.305505 Std devRelated Questions
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