What is Multivariate Analysis Flashcards
What are the four types of numeric data (measurements)?
Nominal, ordinal,
What is nominal data?
Unordered categorical variables.
An example is gender. We can represent men and women with numbers, but the numbers don’t rank over or under each other.
What is ordinal data?
There is an ordering but no implication of equal distance between the different points.
Examples include social class, self-perception of health (each coded from I to V, say), and educational level (no schooling, primary, secondary, or tertiary education)
What is interval data?
Where there are equal differences between successive points on the scale but the position of zero is arbitrary.
The classic example is the measurement of temperature using the celsius or Fahrenheit scales.
What is ratio numeric data?
The highest level of measurement, where one can investigate the relative magnitudes of scores as well as the differences between them. The position of zero is fixed.
Common examples include age, height, weight, and length.
head(dataset)…?
Check out the first six units of the dataset
nrow(dataset)
tells you how many rows
What does co-variance measure?
The covariance of two random variables is a measure of their linear dependence.
What is an alternative way to think about covariance?
Unstandardized correlation coefficient.
How do you standardize the covariance?
Dividing the covariance by the product of the standard deviations of the two variables.
Dividing the covariance by the product of the standard deviations of the two variables produces what quantity?
correlation coefficient
What function do you use to calculate Euclidean distance?
dist( )
What does correlation measure?
It measures the degree (strength) of the relationship between two variables. The Pearson Correlation Coefficient measures the strength of the linear relationship between two variables
