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.

d-bar= ∑d/n= -0.7/ 5= -0.14

Step-by-step 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

solution:

as, mean is defined as sum of all the observations divided by total number of observations.

and , median is mid value of the data whether arranged in ascending order or descending order.

consider, roadsters:

2,3,4,5,6,7,8,9

mean =

also, median= , because number of observations is even, so median is mean of two mid values.

now, coming to bandits

2,3,4,5,6

mean =  

median = 4, as number of observations is odd.

so, roadsters has greater median as well mean than bandits.

→option a is true about the repairs performed on 2 types of cars:

bandits have lower median and mean than roadsters.

i am sorry it just submitted an answer but the answer is 365 boys. hopes this

step-by-step explanation: