Week 1 & 2

Question 1

Why do we need to know data analysis?

Answer 1

There is a problem that needs to be solved and we need data and analytics to properly act on it

Question 2

What is a population?

Answer 2

All entities of interest in a study

Question 3

What is a sample?

Answer 3

A subset or portion of the populations that is randomly chosen

Question 4

What is a dataset?

Answer 4

Table of data containing variables in the column section (horizontal), and observations in the row sections (vertical)

Question 5

What are some examples of variable?

Answer 5

height, gender, income

Question 6

What are some data types?

Answer 6

Numeric vs categorical; Ordinal vs nominal

Question 7

What is numeric?

Answer 7

Meaningful arithmetic that can be performed on

Question 8

What is categorical

Answer 8

otherwise, non numeric (not numbers (?))

Question 9

What is ordinal?

Answer 9

There is a natural ordering of categories

Question 10

What is nominal?

Answer 10

No natural ordering

Question 11

What is a binary decision?

Answer 11

0/1 - a categorical variable with n different categories (n-1) (?)

Question 12

What is binning or discretizing

Answer 12

Categorizing a numeric variable into discrete (not specific)

Question 13

What are some more data types?

Answer 13

Discrete vs continuous; Cross sectional vs time series

Question 14

What is discrete?

Answer 14

Count data (e.g. # of children)

Question 15

What is continunous?

Answer 15

Continuous measurement like weight

Question 16

What is cross sectional?

Answer 16

Cross section of a population in a FIXED time

Question 17

What is time series?

Answer 17

Data that are collected overtime

Question 18

What is an outlier?

Answer 18

An observation that lies outside of the norm (doesn’t mean it’s wrong)

Question 19

What is missing values?

Answer 19

Value of a variable is missing for observation

Question 20

What to do with missing values?

Answer 20

Ignore, average value, or estimate

Question 21

What to do with an outlier?

Answer 21

Run analysis and report with and without the outlier

Question 22

What is the most useful numeric system measure?

Answer 22

Correlation

Question 23

What is the most useful graph?

Answer 23

Scatter plot

Question 24

What is the tool to compare numerical variables across two or more subpopulations?

Answer 24

Side-by-Side Boxplots

Question 25

Tools to study relationships among numeric variables?

Answer 25

Scatterplot, correlation, and covariance

Question 26

What is a scatterplot?

Answer 26

2D graph to plot pairs from 2 numerical variables often used to examine relationships (e.g. temperature and sales)

Question 27

What is correlations and covariance?

Answer 27

Measuring the strength and direction of a LINEAR relationship between 2 numerical variables: X & Y
Note:
X&Y should be paired variables
Xi and Yi for observation i
n: Number of observations

Question 28

What is a perfect positive correlation?

Answer 28

An upward trend scatterplot graph that almost formed a straight line (Value = 1)

Question 29

What is a perfect negative correlation?

Answer 29

A DOWNWARD trend scatterplot graph that almost formed a straight line (Value = -1)

Question 30

What is and what value is a NO CORRELATION?

Answer 30

A scatterplot that is spread out and has no line trend. Value = 0