Analysis of Data
Examining the numerical figures in detail.
Techniques of analysing Data
- Calculation of Percentages
-If in the study of a farm 10 hectares are devoted to coffee, what is the % of the area under coffee?
The table below shows the number of tourists who visited Kenya from various parts of the world in 2006.
- a) Calculate percentage increase of tourists from Africa between 2005 and 2006.
- Measures of Central Tendency
– Outstanding general characteristics of the data.
- a) Arithmetic Mean
– The average
- Easy to calculate for a small data
- Summarises data using a single digit
- Easy to understand and interpret
- Difficult to calculate for grouped data
- Affected by extreme values
- b) Median
– The middle value in a set of data arranged in order.
(I) 20, 50, 90, 100, 150, 180, 200, 220, 240, 300, 360.
(II) 20, 50, 90, 100, 150, 180, 200, 220, 240, 300.
- Easy to calculate in a small data set
- Easy to understand as it’s the value at the middle
- Difficult to calculate in a large data set
- Doesn’t show data distribution
- b) Calculation of Ranges
-Difference between the largest and smallest values. Calculate the range of for the data above.
- c) Mode
– Most frequently recurring value in a set of data.
10, 2, 5, 9, 10, 11, 20, 15, 18, 10.
The mode is 10.
- Easy to find as no calculation is involved
- Easy to understand
- Rarely used as a measure of central tendency
Statistical Presentation of Data