4. Data Visualization & Summarizing Data

Question 1

A visual dimension of a visualization that represents data

Answer 1

Aesthetic

Question 2

Common types of data visualization

Answer 2

1. Scatter plot
2. Line graph
3. Histogram
4. Density chart
5. Bar chart
6. Stacked bar chart
7. Pie chart (usually bad)

Question 3

The variation in a single variable

Answer 3

Univariate statistics

Question 4

The variation between two variables

Answer 4

Bivariate statistics

Question 5

(type of data visualization)
relationship between two numeric variables

Answer 5

Scatter plot

Question 6

(type of data visualization)
change in a numeric variable or proportion over time

Answer 6

Line graph

Question 7

(type of data visualization)
univariate view of a numeric variable

Answer 7

Histogram

Question 8

(type of data visualization)
differences in proportion or mean between categories

Answer 8

Bar chart

Question 9

(type of data visualization)
proportions of various categories

Answer 9

Pie chart (usually bad)

Question 10

What are the two types of Statistics?

Answer 10

1. Descriptive: Describing a given dataset
   Assuming that those data are the population
2. Inferential: Making inferences from a sample to a population. Quantifying the amount of uncertainty around the values you calculate

Question 11

What are the three measures of central tendency?

Answer 11

1. Mean
2. Median
3. Mode

Question 12

What are the measures of spread in numerically describing data? (4)

Answer 12

Range
Quartiles; Inter-Quartile Range (IQR)
Variance
Standard Deviation

Question 13

Mean

Answer 13

Add up all the values and divide by the total number of values

Question 14

An observation that is extreme compared to the rest of the observations.

Answer 14

Outlier

Question 15

Median

Answer 15

Line up the variable in order from lowest to highest and take the middle number; if there are an even number of observations then take the average between the two middle numbers

Question 16

Mode

Answer 16

In classic statistics parlance – the most common value. Prominent peaks in distributions

Question 17

The maximum value minus the minimum value.

Answer 17

Range

Question 18

the data point at which a certain percent of the data is below

Answer 18

percentile (ex. 70th percentile - 70% of people are shorter than you)

Question 19

Quartiles - What is Q1 and Q3

Answer 19

Q1: where 25% of the data are below – i.e. the 25th percentile
Q3: the point where 75% of the data are below – i.e. the 75th percentile

Question 20

Inter-Quartile Range (IQR)

Answer 20

to Q3 minus Q1; a span the covers 50% of the data

Question 21

How far is the typical point away from the center? (standard deviation squared)

Answer 21

Variance

Question 22

Standard Deviation

Answer 22

just the variance, but correcting for the fact that the units are squared… it’s just the square root of the variance

Question 23

n-1

Answer 23

in the formula for standard deviation, we use n-1 for sampling

Question 24

scatter plot

Answer 24

compares two numeric variables to each other

Question 25

line graph

Answer 25

change in one numeric variable over time

Question 26

histogram/box plot

Answer 26

univariate view of 1 numeric variable

Question 27

which charts show us categorical variables?

Answer 27

bar chart, stacked bar chart, and pie chart