Transcript Handling data

Handling Data
Module B2
SADC Course in Statistics
Synopsis of Module
• Overview
– what happens to data once collected
• Organised for the analysis
• tables and graphs are produced
• reports are produced
• Principles
– effective use of a spreadsheet for statistical work
– exploratory data analysis
– good graphs and tables
• Electronic statistics book
– CAST for SADC
Objectives
• Objectives
– See the Module B2 handout
– And individual sessions
• They are on:
–
–
–
–
Management of data
Statistical techniques
Reporting results
IT techniques
Pre-requisites - computing
• Assume some IT skills
–
–
–
–
–
Windows
Simple use of a spreadsheet (Excel)
Simple use of a word processor (Word)
Ideally use of presentation software (Powerpoint)
E-mail plus some experience of the Internet
• If you are a relative beginner
– Windows and Excel are the most important
– Can be done in parallel with this unit
• Otherwise
– Difficult to concentrate on statistics
• You get side-tracked by the need for computer skills
Pre-requisites - statistics
• Module B1
– provides an overview of (Official) statistics
– introduces a range of case studies
– describes ways of collecting data
• If you have not done B1
– or have forgotten the ideas
– read the outline of the module
– case studies will be introduced in this module
Contents of this Module
Session
Contents
1
From data to the report
2
CAST – an electronic statistics textbook
3
Statistical concepts
4 to 8
Producing and presenting good tables
and graphs
9 to 11
Good use of a spreadsheet for statistics
12 & 13
Exploring data before analysis
14
Objectives are the key!
15
Analysing numeric variables
16 & 17
An analysis in practice
18 to 20
Reporting
Session 1:From the data to the report
Three case studies
• Small
– Data on climatic change in Zambia
• Medium
– Data on cropping area in Swaziland
• Large
– Data on agriculture in Tanzania
To illustrate the steps
Learning objectives
• Explain the steps in a study
– once the data are available
• Appreciate the role of data analysis
– in the cycle
• Make initial suggestions
– for improvements in the process
– for timely, high-quality results and reports
Zambia study
• Introduced in Module B1 – Session 8
• Farmers are migrating from Southern Zambia
– citing climate change as the reason
– they can no longer grow the crops as before
• A local NGO believes instead
– acknowledge climate change in general, but believe
what is needed is improved farming practices
wherever farmers locate
• They question the evidence
– for climate change in the pattern of rainfall
as it affects farming strategy
Exercise on Zambia data
• Follow the demonstration: "Zambia
Rainfall”
– Of the work on the data for Moorings
– A station with a long record
– Of daily rainfall data
• Consider the steps that were needed
• And what could be done better in the
future
Swaziland study
• Introduced in Module B1 Session 05
• Annual survey of cropping areas and yields
• Here we look at the data on cropping area
– of maize
• Once they are collected then:
–
–
–
–
How are they computerised?
Checked?
Analysed?
Used?
Exercise on Swaziland study
• Follow the demonstration: “Swaziland Crop
Survey” (You may print the relevant PowerPoint Slides to
follow along with)
– Of the work on the data from the paper records
by 75 enumerators
– to be computerised
– analysed
– sent to the National Met Service for them to use
• Consider the steps that were needed
• And what could be done better in the
future
Tanzania survey
• A huge survey of agriculture in Tanzania
• Involving about 1800 enumerators
• And a main questionnaire of 22 pages
• Given to 3223 households
• A technical report
–
–
–
–
Describes the process of data entry
And checking
Then there is the analysis
And reporting
Excersise on Tanzania study
• Read the document from the technical
report: “Tanzania Agricultural Survey
Chapter 8”
• Consider the the steps in the data
processing.
• What could be done better in future?
Review activity
• What is in common?
– In the steps that are taken
• What is different?
• On improvements
– what suggestions were made?
– what can you suggest?
• Complete the practical/discussion