August 15, 2016
Cross section vs Time Series Data
There are two types of data sets based on the time.
Cross section data is collected on the same point in time. There might be different variables but all of them are collected for the same period of the time. So you won't see any time column.
Time series data expands across periods. Same variable is recorded for different time periods.
Type of Variables
Variables which can be measured.
Countable variables are discrete variables. There is no need to be whole numbers.
Uncountable variables are continuous variables. This contrasts with discrete variables.
Non-numerical variable are called qualitative variables. Sometimes qualitative variables are represented by numbers. But it is useless to perform arithmetic operations on those variables.
Point Estimation and Interval Estimation
Point estimate is a statistic which is inferred from sample data set. Also a closer guess to the population parameter.
Interval estimation describe a range which can contain the value in a population. This contrasts with Point estimation.