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# Form 1 Geography Online Lessons on Statistics

In this Lesson we are going to learn about the Data analysis techniques including: calculation of percentages and the measures of central tendency

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Analysis of Data
-Examining the numerical figures in detail.
Techniques of analysing Data
1. Calculation of Percentages
-If in the study of a farm 10 hectares are devoted to coffee, what is the % of the area under coffee? 10/100×10%
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.
2. Measures of Central Tendency
- Outstanding general characteristics of the data.
a) Arithmetic Mean
• Easy to calculate for a small data
• Summarizes 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.
M= (N+1)/2
(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.