Topic 4

Question 1

Exploratory Data Analysis (EDA)

Answer 1

Visually and statistically summarising, exploring, and understanding the main characteristics of a dataset.

Question 2

Categorical Variables

Answer 2

Variables that aren’t numerical and fall into a category (eg. gender)

Question 3

Ordinal Variables

Answer 3

Categorical variables that are also ordered (eg. bedtime)

Question 4

Contingency Table

Answer 4

Summarises data for two categorical variables

Question 5

Modality

Answer 5

Number of peaks in a distribution

Question 6

Skewness

Answer 6

Indicates whether the data in a distribution leans to the left or right (left skew is actually when there is a peak on the right)

Question 7

What to do with extremely skewed data

Answer 7

Transformations (eg. log transformation)

Question 8

Associated/ Dependent Variables

Answer 8

Variables that show some connection

Question 9

Statistical Inference

Answer 9

Reaching conclusions about the population based on an analysis of a sample

Question 10

Inference

Answer 10

Drawing a conclusion on the full population from a sample

Question 11

Stratified Sampling

Answer 11

Take a random sample from each distinct subgroup, which is made up of distinct observations that are similar in some way

Question 12

Cluster Sampling

Answer 12

Take a random sample of clusters and sample all observations in that cluster

Question 13

Variance in Sample Stats

Answer 13

s^2 = ∑ n, i=1 (xi-x~)^2 / n-1 where x~ is the mean