Measures of Central Tendency, asymmetry, and variability(Udemy Statistics for Data Science and Business Analysis) Flashcards
What is the mean denoted by in greek letters?
u for population and x with a bar over it for a sample
How do you get the mean?
Add up all the components of a dataset, then divide them by their number
What is meant by skewness?
Whether the observations of a dataset are concentrated on one side
What does it mean if the mean is greater than the median?
That there is a positive, or right skew to the data
What does it mean when the mean, median, and mode are all the same?
The data is 0, or no skew
What does it mean when mean is lower than median?
Negative, or left skew
Why is skewness important?
Skewness tells us a lot about where the data is situated
What does Variance Measure?
The dispersion of a set of data points around their mean
Are there different formulas for sample and population variance? Yes/No?
Yes
What is the most common measure of variability for a simple dataset?
Standard Deviation
What is the coefficient of variation?
The ratio of the standard deviation to the mean
What does covariance do?
It gives us a sense of the direction of the way that 2 variables are moving and their relationship, if greater than 0, the variables move together, , if less than 0, they move in opposite directions, if 0, the two variables are independent
What does a correlation of 1 mean?
It is a perfect positive correlation, it means that entire variability of one variable is explainable by other variable
What does a correlation of 0 mean?
That they are absolutely 2 independent variables
