Types of variables and basic summary statistics

Numeric variables

Quantitative - measurable

can be either continuous or discrete

Continuous variables

They can take any value within a range

Discrete variables

They can take specific values within a range

Categorical variables

Qualitative

can be either normal categorical, ordered categorical or binary

Normal Categorical

Divided into different categories, not in a ordered way

Ordered Categorical

Divided into different categories in an ordered way

Binary

Divided into only 2 categories (e.x. Yes or No)

Kinds of scales regarding Numeric variables

1. Interval scale (no real 0)

2. Ration Scale (real 0 exists)

Kinds of scales regarding Categorical variables

1. Nominal scale (divided into different categories, not in an ordered way)

   1. Ordinal scale (divided into different categories in an ordered way)

Measures of central tendency

mean, median(middle point), mode(the most common value)

Measures of dispersion

**dispersion means how much i expect my variable to vary/spread around the central location

variance, standard deviation, interquartile range

Q1

25% is smaller than the value and the rest 75% is bigger

Q2

50% is smaller than the value and the rest 50% is bigger

Q3

75% is smaller than the value and the rest 25% is bigger

IQR =

Q3-Q1

Standard Deviation

The average distance from the mean

the BIGGER the ST, the BIGGER the spread