Week 2 - Descriptive statistics for Single Variable

Question 1

define (relative) frequency distribution
give an example

Answer 1

Distribution of the number of observations (“frequency”) or the proportion/percentage of observations (“relative frequency”) across different values of a variable

eg. perception of the economy ces 2019
- over the past year, has canada’s economy gotten better, woorse, or stayed about the same

Question 2

To describe the central tendency, what are the three summary statistics (numerical summaries of data

Answer 2

Mode (most common value)
Median (middle value)
mean (average value)

Question 3

Mode/modal range

Answer 3

Mode (most common value)
- the value of the variable with the largest number of observations
- modal value is the range of values of the variable with the largest number of observations (on the histogram its the tallest bin)

Question 4

Median

Answer 4

order observations from the smallest value of y to the largest value of y

median is the middle value of this ordered sample

it splits the sample into two groups with equal numbers

Question 5

mean

Answer 5

mean = average

y-hat is often used to denote the mean

sum of the values of y for all observations, divided by the number of observations