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VCE 12 General 2023

4.03 Smoothing with moving median

Worksheet
Moving median tables
1

For each of the following tables calculate the value of x, y, \text{ and }z:

a
\text{Time period}\text{Data}\text{3-Point Median}
154
245x
35047
4y47
54247
64848
74948
843z
94847
104747
113946
1246
b
\text{Time period}\text{Data}\text{5-Point Median}
19.2
211
310.7x
49.510.5
59.610.5
6y10.5
711.511.4
811.511.4
911.411.4
1010.9z
1110.5
1212.2
c
\text{Time period}\text{Data}\text{3-Point Median}
1534
2346x
3213346
4y678
5874753
6753753
7679679
8186z
9348348
10547369
11369486
12486
d
\text{Time period}\text{Data}\text{5-Point Median}
119.1
210.5
318.2x
412.414.1
529.814.1
6y14.1
7714.1
814.214.1
96.98.7
1027.6z
118.7
120.4
2

The Smith family review the money they spent on groceries each month in 2019. The results are given in the table:

Calculate the values of a, b, \text{ and } c.

\text{Time period}\text{Data}\text{3-Point Median}
\text{Jan}986
\text{Feb}10041004
\text{Mar}1051a
\text{Apr}10101010
\text{May}9781006
\text{Jun}b1006
\text{Jul}10151015
\text{Aug}10431043
\text{Sep}1071c
\text{Oct}10281053
\text{Nov}10531053
\text{Dec}1092
3

The Reid family review the money they’ve spent on household bills. The results are given in the table:

Calculate the values of a, b, \text{ and } c.

\text{Time period}\text{Data}\text{3-Point Median}
\text{Jan}1017
\text{Feb}9751017
\text{Mar}1022a
\text{Apr}10061021
\text{May}10211021
\text{Jun}b1041
\text{Jul}10421041
\text{Aug}10051042
\text{Sep}1052c
\text{Oct}10611052
\text{Nov}10341061
\text{Dec}1064
Moving median graphs
4

The following time series graph shows the temperature (\degree \text{C}) recorded for the 29 days of February in a particular leap year:

Calculate the 5-median smoothed temperature for:

a

Day 12

b

Day 14

5

The following time series graph shows the number of days it rained each month in a year:

Calculate the 5-median smoothed number of days for the following months:

a

April

b

July

c

October

6

The following time series plot shows the number of passengers who flew with an airline each month from 1955 to 1958:

The dot above 1955 corresponds to the number of passengers in January 1955. Which value is the five-median smoothed number of passengers for August 1955 closest to?

A
320
B
355
C
375
D
405
7

For each of the following Time Series graphs, calculate, plot and connect the six 3-point moving medians to smooth the data:

a
1
2
3
4
5
6
7
8
9
\text{Time}
2
4
6
8
10
12
14
y
b
1
2
3
4
5
6
7
8
9
\text{Time}
30
35
40
y
c
1
2
3
4
5
6
7
8
9
\text{Time}
1
2
3
4
5
6
7
8
9
10
11
12
y
8

For each of the following Time Series graphs, calculate, plot and connect the six 5-point moving medians to smooth the data:

a
1
2
3
4
5
6
7
8
9
10
\text{Time}
9
10
11
12
13
14
15
16
17
18
y
b
1
2
3
4
5
6
7
8
9
10
\text{Time}
44
46
48
50
52
54
y
c
1
2
3
4
5
6
7
8
9
10
\text{Time}
5
10
15
20
25
30
35
40
45
y
9

The time series plot shows the minimum rainfall recorded at the weather station each month plotted against the month number (January = 1).

Rainfall is recorded in millimetres. The data was collected over a period of one year.

Calculate, plot and connect 8 additional points to create a 5-point moving median graph.

1
2
3
4
5
6
7
8
9
10
11
12
\text{Month}
10
20
30
40
50
60
70
80
90
\text{Rain}
10

The time series plot shows the average rainfall, in millimetres, recorded at the weather station over twelve weeks:

Calculate, plot and connect 8 additional points to create a 5-point moving median graph.

1
2
3
4
5
6
7
8
9
10
11
12
\text{Week}
10
20
30
40
50
60
70
80
90
\text{Rain}
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Outcomes

U3.AoS1.28

identify key qualitative features of a time series plot including trend (using smoothing if necessary), seasonality, irregular fluctuations and outliers, and interpret these in the context of the data

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