Moving Averages

Example

The table below represents test results for two students from last year’s 11M2.

Surname Forename Tutor P1 P2 P3 P4 P5 P6 P7 P8 P9 P10

ALI Mubarik OB 49 30 52 48 35 43 39 36 40 47

BROMLEY Dean CB 36 38 56 72 43 52 43 40 62 38

a) Obtain the three point moving average for each of these students.

b) Plot the data onto a set of axes and draw a trend line for each student.

Example

The list below represents the number of children absent from school for a

fifteen-day period.

Day 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Number Absent

18 12 8 9 8 17 12 8 8 6 15 10 8 6 5

a) Why is a five-point moving average more suitable for this data?

b) find the five-point moving average for this data.

c) Plot the data onto a set of axes and draw the trend line.

Example

The quarterly phone bills for one family over a three-year period are given in the

table below.

Year 1998 1999 2000

Month Mar Jun Sep Dec Mar Jun Sep Dec Mar Jun Sep Dec

Total Bill (£) 98 86 42 102 101 88 47 103 105 91 51 121

a) Draw a graph for the data

b) Calculate the four quarterly moving averages for the data.

c) Plot the moving averages on the same graph as the original data, joining up

the points with a dotted line.

d) What is the trend in payments over this period?