DATA TABLES… KINDS OF VARIABLES… Qualitative vs. Quantitative Discrete vs. Continuous DISPLAYING...
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Transcript of DATA TABLES… KINDS OF VARIABLES… Qualitative vs. Quantitative Discrete vs. Continuous DISPLAYING...
DATA TABLES…
KINDS OF VARIABLES…
Qualitative vs. Quantitative
Discrete vs. Continuous
DISPLAYING a QUALITATIVE VARIABLE
MORE about HISTOGRAMS
DATA TABLE
parties politics salary singer
5 mod. 80000 1.5
1 liberal 35000 3
3 liberal 3
2 mod. 40000 4
2 liberal 40000 0
DATA TABLE
parties politics salary singer
5 mod. 80000 4.5
1 liberal 35000 3
3 liberal 3
2 mod. 40000 4
2 liberal 40000 0
Rows
Columns
CASES
INDIVIDUALS
whatever
VARIABLES
Kinds of Variables
QUALITATIVE —
Nominal — Just labels
Ordinal — Order matters
QUANTITATIVE —
Discrete — Only certain values(for example, whole numbers)
Continuous — Any value is possible
(at least in some range)
DISPLAYING ONE QUALITATIVE VARIABLE
Frequency table…
Bar chart…
Pie chart…
Frequency table - politics
VALUE COUNT
Liberal 20
Moderate 3
Conservative 2
TOTAL 25
Frequency table - politics
VALUE COUNT PERCENT(of column)
Liberal 20 80 %
Moderate 3 12 %
Conservative 2 8 %
TOTAL 25 100%
Frequency table – politics (Swarthmore)
VALUE COUNT PERCENT(of column)
Liberal 46 64%
Moderate 22 31%
Conservative 4 6%
TOTAL 72 100%
Frequency table – singing
VALUE COUNT PERCENT
1 10 39 %
2 6 23 %
3 6 23 %
4 2 8 %
5 2 8 %
TOTAL 26 100 %
Frequency table – singing
VALUE COUNT PERCENT
1 10 39 %
2 6 23 %
3 6 23 %
4 2 8 %
5 2 8 %
TOTAL 26 101 %
Frequency table – singing
VALUE COUNT PERCENT
1 10 38 %
2 6 23 %
3 6 23 %
4 2 8 %
5 2 8 %
TOTAL 26 100 %
Frequency table – singing (Swarthmore)
VALUE COUNT PERCENT
1 16 22%
2 16 22%
3 23 32%
4 12 17%
5 5 7%
TOTAL 72 100%
12345
Singing
0
2
4
6
8
10
12
1 2 3 4 5
EQUAL-AREA PRINCIPLE
Areas are in proportion to data values.
Salaries (Swarthmore)
600000 60000 50000 60000 50000 30000
50000 50000 30000 very small 250000
75000 30000 70000 60000
70000 80000 125000 50000
35000 65000 50000 70000 80000
200000 30000 400000 72500 60000
80000 40000 30000 150000 75000 40000
120000 40000 40000 20000 60000
500000 75000 30000 60000 45000
40000 85000 35000 90000 150000
150000 50000 100000 45000 30000 80000
100000 50000 1000000 100000 50000
Salaries - $20,000 bin sizes
$50,000 bin sizes
$100000 bin sizes
Constructing a histogram…
Define binsAll the same size ? Easier if they are, but…Boundaries – ENDPOINT RULE
Make a frequency table for your chosen bins…
Construct histogram…
Shape of a distribution…
Symmetrical ?Skew – right or left
UnimodalBimodal Multimodal
Outliers