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Math:- Chapter 12 (12.2 Samples and Populations (Collecting Data (Once…
Math:- Chapter 12
12.2 Samples and Populations
Collecting Data
Once data is collected, it can be organised, analyzed and interpreted
A survey is a process of collecting data. If every member if a target poplutaion is surveyed, the process is called a census
A census is conducted in Australia every 5 years to obtain an accurate profile of Australians
Due to limitations in time, cost and practicality, in many cases a sample of the population is selected at random to prevent biased results
Surveys
Administered with the aid of a questionnaire
The success of obtaining relevent data is based on how good the questions are
Collecting data by survey is the form most frequently used.
Questionnaires
Data should be in a form which can easily be analyzed. Questions can be open or closed
Open questions are those which answers can have boundaries or guides
Open questions are often difficult to analyze and classify
Closed questions require the respondant to answer within a category or guide
Selcting Samples
The sample must be as close as possible to that of the population
Random selecting technique
Primary and Secondary Data
Primary data is data you have collected yourself
Observation is looking at something or observing the reaction of someone
Measurement involves using a measuring device to collect the data
Surveys involve questionnaires
Experiment involves conducting experiments with people or things to collect data
Secondary Data is data someone else has collected
Paper, Electronic, Government Sources, General Business Sources, Media