Stats Flashcards
Numerical data
Data is on numbers eg. shoe size
Categorical data
Data is text eg. hair colour
Discrete data
Whole numbers eg. number of people in a family
Continuous data
Can be decimals eg. height
Ordinal data
categorical data that can be put in order
Nominal data
Categorical data that cant be put in order eg. phone brand
Primary data
First hand data
Secondary data
Secondary data
Population
Entire group being studied
Sample
Group selected from population
Outlier
Extreme value that is not similar to other values in the data set
Collecting data
Sample must be randomly selected - prevent bias
Sample must represent population
Sample must be sufficiently large
Bar chart
Individual bars + axis must be labelled
Even scale
use a ruler
Categorical data
Trend graphs
Label axis
Scale
Line plot
Clear columns of X
Label columns
Can be used for categorical data
Pie charts
Circle drawn with compass
Angles measured with protractor
Label angles and sectors
Can be used for categorical data
Histogram
Scale along both axis
Axis labelled + evenly drawn with ruler
Can be used for continuous numerical data
Stem and leaf plot
First column = stem (the tens)
Second column = leaf (units)
Include key ed. 3 I 4 = 34
Separate leaves with comas
Mean - def
The sum of all the values devided by the number of values
The mean - pros + cons
Pros: Uses all the data
Cons: Affected by outliers
Mode - def
The number that appears most often
Mode - Pros + cons
Pros: Not affected by outliers, can be used for any type of data
Cons: Does not use all the data
Median - def
Middle value when values are in numerical order
Median pros + cons
Pros: Easy to calculate, not affected by outliers
Cons: Does not use all data
Range
Difference between highest + lowest value
