Слайд 2

Starter

In the back of your book, draw a Bar Chart to show

Starter In the back of your book, draw a Bar Chart to show the following information;
the following information;

Слайд 3

Starter


Height (cm)

Frequency

0

5

20

15

10

100

25

120

180

160

140

200

Starter Height (cm) Frequency 0 5 20 15 10 100 25 120 180 160 140 200

Слайд 4

Starter

Problems
1) The data is continuous so there should be no gaps
2) 150

Starter Problems 1) The data is continuous so there should be no
– 160 has the same height as 120 – 140, even though it represents a smaller range
A Histogram will correct both of these problems!

Height (cm)

Frequency

0

5

20

15

10

100

25

120

180

160

140

200

Слайд 5

Histograms

20

25

30

25

20

Frequency

0.5

160 < x ≤ 200

2.5

150 < x ≤ 160

3

140 < x ≤

Histograms 20 25 30 25 20 Frequency 0.5 160 2.5 150 3
150

1.25

120 < x ≤ 140

1

100 < x ≤ 120

Frequency Density

Height (cm)

To take into account the size of the group, we calculate ‘Frequency Density’

Frequency Density

Frequency

Classwidth

=

Frequency Density

20

20

=

1

=

30

10

3

=

25

20

1.25

=

20

40

0.5

=

25

10

2.5

=

Слайд 6

Histograms

100

140

130

120

150

160

180

170

110

200

190

1

2

3

0

Frequency Density

Height (cm)

Histograms 100 140 130 120 150 160 180 170 110 200 190

Слайд 7

Histograms

With a Histogram, area represents Frequency, not the height

eg) The first group is

Histograms With a Histogram, area represents Frequency, not the height eg) The
a rectangle measuring 20 by 1
20 x 1 = 20 so there were 20 people in the group

eg) The fifth group is a rectangle measuring 40 by 0.5
40 x 0.5 = 20 so there were 20 people in the group

Слайд 8

Histograms

To take into account the size of the group, we calculate ‘Frequency

Histograms To take into account the size of the group, we calculate
Density’

Frequency Density

Frequency

Classwidth

=

Frequency Density

=

10

40

0.25

=

2

20

70 < x ≤ 80

7

35

65 < x ≤ 70

4

20

60 < x ≤ 65

1.8

18

50 < x ≤ 60

1.5

15

40 < x ≤ 50

0.25

10

0 < x ≤ 40

Frequency Density

Frequency

Speed (mph)

18

10

1.8

=

35

5

7

=

20

5

4

=

15

10

1.5

=

20

10

2

=

Слайд 9

Histograms

0

80

40

30

20

10

60

50

70

10

2

8

6

4

0

Frequency Density

Speed (mph)

Histograms 0 80 40 30 20 10 60 50 70 10 2

Слайд 10

Histograms

0

80

40

30

20

10

60

50

70

10

2

8

6

4

0

Frequency Density

Speed (mph)

Group 1 is a 40 by 0.25 rectangle
40 x 0.25

Histograms 0 80 40 30 20 10 60 50 70 10 2
= 10
So 10 people in the group

Remember that Area represents Frequency!

Group 5 is a 5 by 7 rectangle
5 x 7 = 35
So 35 people in the group

Слайд 11

Plenary

(4)

33g

103g

Frequency Density

0.5

2.2

5.3

0.5

Plenary (4) 33g 103g Frequency Density 0.5 2.2 5.3 0.5

Слайд 12

Plenary

1

Frequency Density

6

5

4

3

2

Egg Weight (g)

Plenary 1 Frequency Density 6 5 4 3 2 Egg Weight (g)
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