Chapter 6 (Data Summary)

Question 1

What is categorical data?

Answer 1

Data values have values that correspond to categories or types.

Question 2

What is anther name for categorical data?

Answer 2

Nominal, or qualitative

Question 3

What is numerical data?

Answer 3

Data have integer or real number values.

Question 4

What is anther name for numerical data?

Answer 4

Quantitative

Question 5

What is the distribution of a variable?

Answer 5

The set of all values the variable can take in, and their associated probabilities.

Question 6

What is a bar chart?

Answer 6

A chart that consists of bars with heights proportional to the number of observations in the category

Question 7

What type of data do bar charts represent?

Answer 7

Categorical data

Question 8

What are bar charts good for?

Answer 8

Comparing categories!

Question 9

What does a pie chart emphasize?

Answer 9

The proportion of the total data set that falls into each category.

Question 10

How to find the portion of a pie chart for a given category?

Answer 10

The angle will be r/n * 360 degrees

r = category value
n = # of total observations

Question 11

What data type do pie charts display?

Answer 11

Categorical

Question 12

What is a histogram?

Answer 12

Similar to a bar chart, a histogram has bars, but is used to present numerical data, not categorical.

Question 13

What is a smoothed histogram?

Answer 13

A curve that summarizes the features of a histogram.

Question 14

How is data displayed in a histogram?

Answer 14

It is separated into “classes” or “bins”, and the count or percentage of the data in each class is represented by a bar.

Question 15

What does plotting data enable us to do?

Answer 15

Look for overall patterns or deviations from the pattern in the data.

Question 16

What are the extreme values (left and right ends) of a distribution called?

Answer 16

The tails

Question 17

What is a skewed distribution?

Answer 17

A distribution with a long tail

Question 18

What does a right skewed distribution look like?

Answer 18

The distribution has a long right tail

Question 19

What does a left skewed distribution look like?

Answer 19

The distribution has a long left talk

Question 20

What is a mode?

Answer 20

A peak in a distribution.

Question 21

What is unimodal?

Answer 21

The distribution has one mode

Question 22

What is bimodal?

Answer 22

The distribution has two modes.

Question 23

What is multimodal?

Answer 23

A distribution with multiple modes in it.

Question 24

What does a symmetric distribution look like?

Answer 24

It is the same in both of its tails. It can be flipped on the vertical axis in its middle.

Question 25

What are outliers?

Answer 25

Observations that are apart from the majority of the data.

Question 26

What to do when a data set has outliers?

Answer 26

Look for an explanation of the outliers. If they aren’t erroneous, do NOT remove them.

Question 27

What is sample mean?

Answer 27

Sum of the values in a list divided by the number of values in the list.

Question 28

What is the median?

Answer 28

The middle data point. If the number of observations is even, then the median is the mean of the two middle points.

Question 29

What is the numerical mode?

Answer 29

The value that occurs the most often.

Question 30

What is the pth percentile?

Answer 30

A value such that p% of the values are smaller than it

Question 31

What is the lower quartile?

Answer 31

25th percentile

Question 32

What is the interquartile range?

Answer 32

The difference between the upper and lower quartile.

Question 33

What kind of data does a boxplot show?

Answer 33

Numerical data!

Question 34

What does a boxplot look like?

Answer 34

• a central box between the upper and lower quartile
• a line through the box at the median
• “whiskers” extending to the minimum and maximum values.