1. Bar charts and Histograms

2. Frequency distribution
Definition: It is a list of values from a sample.
Example: Number of children per family
Size = {1,2,2,2,4,2,2,1,2,2,2,3,1,2,3,2,2,1,2,1,1,2,3,2,1}
Size
Absolute Frequency 1 7 2 14 3 4
Total 25

3. Absolute and relative frequencies, and percentage
Size
Absolute Frequency
Relative
Frequency
Percentage 1 7
0.28 28 2 14
0.56 56 3
0.12 12 4
0.04
Total 25
100

4. Bar chart
Usually, categorical and nominal data are visualized by using a bar chart.
Example: Number of children in a family
Size = {1,2,2,2,4,2,2,1,2,2,2,3,1,2,3,2,2,1,2,1,1,2,3,2,1}

5. Histogram If the x-axis is continuous, then we use an histogram
Example: Scores on an empathy scale
Score = {60, 38, 41, 45, 40, 75, 31, 35, 45, 46, 55, 61, 40, 15, 58, 71, 46, 53, 65, 54, 41, 56, 45, 65, 69, 50, 54, 41, 57, 44, 75, 30, 44, 30, 63, 44, 58, 34, 33, 66, 49, 42, 58, 70, 28, 49, 47, 47, 58, 38}
Since there is too many data, we have to regroup them in bins.

6. Histogram
Size of bins = 1

7. Histogram
Size of bins = 5

8. Histogram
Size of bins= 10

9. Histogram
Size of bins = 20

10. Frequency distribution: ShapesII
III IV V VI
VII
Modality
Kurtosis
Skewness
- Unimodal :
I, IV,V, VI, VII
- Mesokurtic :
I, II
- symetric :
I, II, III, V, VI
- Bimodal : II
- Platykurtic : V
- asymetric :
IV, VII
- Rectangular:
III
- Leptokurtic :
IV,VI,VII