Charts And Graph
Recognize the difference between grouped and ungrouped data
Construct a frequency distribution
Construct a histogram, a frequency polygon, an ogive, a pie chart,
Ungrouped data
have not been summarized in any way
• are also called raw data
•
Grouped data
•
have been organized into a frequency distribution
42
26
32
34
57
30
58
37
50
30
53
40
30
47
49
50
40
32
31
40
52
28
23
35
25
30
36
32
26
50
55
30
58
64
52
49
33
43
46
32
61
31
30
40
60
74
37
29
43
54
Ages of a Sample of
Managers from
Urban Child Care
Centers in the
United States
Class IntervalFrequency
20-under 30
6
30-under 40
18
40-under 50
11
50-under 60
11
60-under 70
3
70-under 80
1
42
26
32
34
57
30
58
37
50
30
53
40
30
47
49
50
40
32
31
40
52
28
23
35
25
30
36
32
26
50
55
30
58
64
52
49
33
43
46
32
61
31
30
40
60
74
37
29
43
54
Range = Largest - Smallest
= 74 - 23
= 51
Smallest
Largest
Note: One can order the data values from smallest to largest to help find the range.
The number of classes should be between 5 and 15.
•
•
Fewer than 5 classes cause excessive summarization. More than 15 classes leave too much detail. Class Width
•
•
•
Divide the range by the number of classes for an approximate class width
Round up to a convenient number
51
So if the number of classes
Approximat
e Class
Width is
= 6, then
= 8.5
6
Class Width = 10
The midpoint of each class interval is called the class midpoint or the class mark.
Class Midpoint = class beginning point +
1
= 30 + 10
2
= 35
1 class width
2
The relative frequency is the proportion of the total frequency that is any given class interval in a frequency distribution.
Relative
Class Interval Frequency Frequency
20-under 30
6
.12
6
30-under 40
18
.36
50
40-under 50
11
.22
50-under 60
11
.22
18
60-under 70
3
.06
50
70-under 80
1
.02
Total
50
1.00
The cumulative frequency is a running total of frequencies
through
Recognize the difference between grouped and ungrouped data
Construct a frequency distribution
Construct a histogram, a frequency polygon, an ogive, a pie chart,
Ungrouped data
have not been summarized in any way
• are also called raw data
•
Grouped data
•
have been organized into a frequency distribution
42
26
32
34
57
30
58
37
50
30
53
40
30
47
49
50
40
32
31
40
52
28
23
35
25
30
36
32
26
50
55
30
58
64
52
49
33
43
46
32
61
31
30
40
60
74
37
29
43
54
Ages of a Sample of
Managers from
Urban Child Care
Centers in the
United States
Class IntervalFrequency
20-under 30
6
30-under 40
18
40-under 50
11
50-under 60
11
60-under 70
3
70-under 80
1
42
26
32
34
57
30
58
37
50
30
53
40
30
47
49
50
40
32
31
40
52
28
23
35
25
30
36
32
26
50
55
30
58
64
52
49
33
43
46
32
61
31
30
40
60
74
37
29
43
54
Range = Largest - Smallest
= 74 - 23
= 51
Smallest
Largest
Note: One can order the data values from smallest to largest to help find the range.
The number of classes should be between 5 and 15.
•
•
Fewer than 5 classes cause excessive summarization. More than 15 classes leave too much detail. Class Width
•
•
•
Divide the range by the number of classes for an approximate class width
Round up to a convenient number
51
So if the number of classes
Approximat
e Class
Width is
= 6, then
= 8.5
6
Class Width = 10
The midpoint of each class interval is called the class midpoint or the class mark.
Class Midpoint = class beginning point +
1
= 30 + 10
2
= 35
1 class width
2
The relative frequency is the proportion of the total frequency that is any given class interval in a frequency distribution.
Relative
Class Interval Frequency Frequency
20-under 30
6
.12
6
30-under 40
18
.36
50
40-under 50
11
.22
50-under 60
11
.22
18
60-under 70
3
.06
50
70-under 80
1
.02
Total
50
1.00
The cumulative frequency is a running total of frequencies
through