Data And Statistics Flashcards
What are the three methods of data collection?
Experiment, observation, survey
How do you calculate the sample size for a survey to avoid bias?
√population size
Square root
What are the column headings of a distribution table (in order from left to right)?
Score, tally, frequency
What is a histogram?
Similar to a column graph, however there are no gaps in between the bars (apart from at the start between the axis and first bar). It shows the data shown in a frequency distribution table.
Describe how to collect primary data
Before collecting any primary data, it must be clear what data are to be collected.
A decision must be made as to the method of collection.
The advantages and disadvantages of the collection method must be acknowledged.
The reason for the data collection should be clear from the outset.
Describe how to obtain secondary data. Give the five categories of sources.
Secondary data is data that had already been collected by other people. It can be collected from a range of sources. Such as
– Paper — books, journals, magazines, company reports
– Electronic — online databases, internet, broadcasts, DVDs
– Government sources — ABS provides a wealth of statistical data
– General business sources — academic institutions, stockbroking firms, sporting clubs
– Media — newspapers, TV reports.
What does ‘f’ mean?
Frequency
What does x mean in statistics?
Score
When is the mean appropriate as a measure of centre?
When no extreme values or outliers distort the picture.
When is the median appropriate as a measure of centre?
When outliers are present
When is the mode appropriate as a measure of centre?
When the most common result is significant
What is it called when you group data because there is too much of it?
Class intervals
What is the column that must be included when grouping data into classes?
The midpoint OR class centre
What symbols are used for class intervals when trying to say eg. Including 1, 2 & 3 but not 4?
1-
When is data said to be positively skewed?
When there is a greater amount of data towards the lower end of the distribution (the left side of the graph). There is less on the right side.
