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.

  1. 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

Advantages

  1. Easy to calculate for a small data
  2. Summarises data using a single digit
  3. Easy to understand and interpret

Disadvantages

  1. Difficult to calculate for grouped data
  2. Affected by extreme values

b) Median

– The middle value in a set of data arranged in order.

M= (N+1)/2

  1. 20, 50, 90, 100, 150, 180, 200, 220, 240, 300, 360.
  2. 20, 50, 90, 100, 150, 180, 200, 220, 240, 300.

Advantages

  1. Easy to calculate in a small data set
  2. Easy to understand as it’s the value at the middle

Disadvantages

  1. Difficult to calculate in a large data set
  2. 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.

Advantages

  1. Easy to find as no calculation is involved
  2. Easy to understand

Disadvantage

  1. Rarely used as a measure of central tendency
  2. Statistical Presentation of Data

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