Martin earned the following scores on his last five tests. 98, 78, 84, 75, 91 what is the mean absolute deviation of his scores?

Step-by-step explanation:

find the average of his scores:

98 +78+84 +75 +91 = 426/5 = 85.2

now find the difference between the average and each test score:

98 - 85.2 = 12.8

85.2 -78 = 7.2

85.2 - 84 = 1.2

85.2 -75 = 10.2

91-85.2 = 5.8

 total those and divide by the number of tests

12.8 + 7.2 + 1.2 +10.2 +5.8 =37.2/5 = 7.44

6, 10

9, -13

12, -21

18, -23

step-by-step explanation:

you just add 6 to the x-coordinate and subtract 10 from the y-coordinate.

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."