Flashcards in Statistics - Representations of data Deck (12):
What is an outlier?
An extreme value that lies outside overall pattern of data
What are the common definition of an outlier?
Any value that is:
Greater Q3 + k x IQR
Less than Q1 - k x IQR
What is an anomaly?
Outlier that is removed from data since it is clearly an error and it would be misleading to keep it
What is cleaning the data?
The process of removing anomalies from a data set
What features does a box plot show with lines?
Q1, Q2, Q3
Outliers are a cross
What should be done when comparing two box plots?
Use the same scale
Compare medians, IQR and extremes
What is bivariate data?
Data which has pairs of values for two variables
What is usually plotted on each axis?
x-axis - independent variable
y-axis - dependent variable
What is a causal relationship?
When a change in one variable causes a change in the other
Correlation doesn't show causation
What is the regression line?
Straight line that minimises the sum of the squares of the distance of each data point from the line
What is the equation of the regression line?
y = a + bx