TYPES OF DATA
Data can be
quantitative (numerical data) or
qualitatitive (non-numerical data).
Quantitative data can be
discrete (when it can only take certain values) or
continuous (can take any value in a certain range)
When spread of data is too big we often group the data in a frequency table using class intervals. Grouping data can result in loss of accuracy in both calculations & presentations.
Bivariate data are used when you measure 2 related things e.g. height & weight of children.
Categorical data is data sorted into categories (groups)
Ranked data have values that can be ranked (put into order)
Primary data - collected by person who is going to use it. Not yet been processed.
Advantages: known accuracy, know how obtained.
Disadvantages time consuming, expensive.
Secondary data - collected by someone else.
Advantages cheap & easy to obtain.
Disadvantages – might be out of date, have mistakes, don’t know how collected.
Experiments – one variable is controlled (explanatory or independent variable) while its effect on the other variable (response or dependent…