More on Histograms Density Histograms
More on Histograms
Density Histograms
Density =
This ensures that the area of the rectangle is
proportional to the corresponding frequency.
Make a Density Histogram
Class Freq Rel.Freq. Density
0 - 0.1 4
0.1 - 0.2 8
0.2 - 0.4 10
0.4 - 2.0 12
L1
Freq
L3
Width
4 0.11765 0.1 1.1765
8 0.23529 0.1 2.3529
10 0.29412 0.2 1.4706
12 0.35294 1.6 0.22059
Use you
GDC to
help!
Make the
Density
Histogram
Class Interval Density
0 – 0.1 1.18
0.1 – 0.2 2.35
0.2 – 0.4 1.47
0.4 – 2.0 0.221
Density
Class Interval
Class Freq Rel. Freq. Density
0 - 10 6
10 - 20 12
20 - 40 20
40 - 60 18
60 - 100 14
Class Freq Rel. Freq. Density
0 - 10 6 0.00857
10 - 20 12 0.01714
20 - 40 20 0.01429
40 - 60 18 0.01286
60 - 100 14 0.005
Class Freq Rel. Freq. Density
0 -100 24
100 - 300 28
300 - 600 30
600 - 1000 26
Class Freq Rel. Freq. Density
0 -100 24 0.22222 0.00222
100 - 300 28 0.25926 0.0013
300 - 600 30 0.27778 0.00093
600 - 1000 26 0.24074 0.0006
Graph the following:
Interval frequency
20 – 40 35
40 – 60 27
60 – 100 20
100 - 200 10
200 – 800 28
Interval Density
20 – 40 0.01458
40 – 60 0.01125
60 – 100 0.00417
100 - 200 0.00083
200 - 800 0.00039
Bivariate
Ojive – Cumulative Frequency
Graph 1. Find the cumulative frequencies
2. Plot beginning of class on the horizontal axis and
the cumulative frequencies on the vertical axis.
Ages Frequency
13 - 19 5
19 - 25 8
25 - 31 11
31 - 37 20
37 - 43 6
Time Series – Line plot that plots each
observation against the time of the observation.
Year Life
Expectancy
1900 48.3
1910 58.1
1920 54.6
1930 61.6
1940 65.2
1950 71.1
1960 73.1
1970 74.7
1980 77.5
1990 78.8
2000 79.5
Ex: Construct a Time Series Graph
A transit manager
wishes to use the
following data for a
presentation showing
how Port Authority
Transit ridership has
changed over the years.
Year Ridership (in millions)
1990 88
1991 85
1992 76
1993 77
1994 75
Time Series Graph
65
70
75
80
85
90
1990 1991 1992 1993 1994
Freq
Year Ridership (in millions)
1990 88
1991 85
1992 76
1993 77
1994 75
Scatter plots
Graphs an ordered pair.
Put the data in L1 and L2
Press 2nd Stat Plot to turn the graph on
Press ZOOM 9 to graph
Create a scatterplot.
Wt Cl
(kg)
Total
Lifted
(kg)
46 140
50 127
54 165
59 167
64 192
70 185
76 198
83 200
Find the Line of Best Fit
Wt Cl
(kg)
Total
Lifted
(kg)
46 140
50 127
54 165
59 167
64 192
70 185
76 198
83 200 y= 1.89x + 53.0
Let’s try another one! Use it to
predict the sodium for 40 g of fat.
Fat (g) Sodium
19 920
31 1500
34 1310
35 860
39 1180
39 940
43 1260
y = 6.08x + 930
Prediction:
y = 6.08(40) + 930
y = 1173.20
Homework
Worksheet