Chapter 2-3 Flashcards
What is ordinal data?
- a type of categorical data
- categories with a natural order
- ex cancer stage
What is nominal data?
- a type of categorical data
- unordered categories or classes
- ex. Gender or cancer
What is discrete data?
- a quantative type of data
- numbers represent measurable quantities, restricted to specific values
- ex. # of days in hospital
- integer values (0,1,2)
- finite # of possible values
What is continuous data?
- quantative type of data
- numbers represent measurable quantities with no respect to values
- ex. Blood pressure heigh
- infinite number of possible values
When to use bar plots?
- for categorical variables or discrete variables with a limited number of possible values
When to use histograms?
For discrete variables with many possible values and for continuous variables
What does the mean and median measure?
The central tendency of the distribution
What are the five numbers graphed in the box plot?
1st quartile 3rd quartile Minimum Maximum Median
What is the mean?
The ordinary arithmetic average of the observations
Symbol xbar
What is the median?
The MIDDLE value of the data
What does the standard deviation measure?
SD - measures the spread about the mean
What is variance ? S^2?
The average of the squared deviations and the SD is it’s square root
What is measured by the inter quartile range?
The first and third quartiles
The middle half of the data lies between them
What does standard deviation (SD) measure?
Spread about the mean
What is variance?
S^2 and it is the average of the squared deviations
-SD is its square root
