Question

Can anyone find d-bar (the d with the line over it) and explain it to me? For this problem five trials are done at eight am and then twelve am. The eight am trials are 98.4, 98.6, 97.8, 97.1, and 97.5. The 12am ones are 98.9, 99, 97.9, 96.6, and 97.7. The correct answer is -0.14 but I can't get that answer.

Answer 1

d-bar= ∑d/n= -0.7/ 5= -0.14

Explanation:

Eight am 12 am difference (8:00am- 12:00 am)= d

98.4 98.9 (98.4-98.9=) -0.5

98.6 99 (98.6-99=) -0.4

97.8 97.9 (97.8-97.9=) - 0.1

97.1 96.6 (97.1-96.6=)+0.5

97.5 97.7 (97.5-97.7=)-0.2

∑ -0.7

d= difference between 8 am and 12 am

First we subtract the 12.00 am times from 8:00 am times.

Then we add all the differences to get the total difference ∑d.

∑d= -0.7= total of the difference between two times.

n= number of observations=5

Putting the values in the formula would give the answer.

d-bar= d`= ∑d/n= -0.7/ 5= -0.14