chapter 1: picturing distributions with graphs

Question 1

Individuals

Answer 1

Particular things

Question 2

Population

Answer 2

Set of individuals

Question 3

Variable

Answer 3

an attribute of an individual.

Question 4

value (of a variable)

Answer 4

any way that that variable could be exhibited by an individual

Question 5

True or False: every individual must have only a single value for any given variable

Answer 5

True

Question 6

Data

Answer 6

numbers with a context, or, values of variables for the individuals in a population

Question 7

Dataset

Answer 7

The particular data that we are presented with

Question 8

observation

Answer 8

a member of our dataset

Question 9

sample

Answer 9

That part of the population from which our observations come

Question 10

The size of a dataset (or sample)

Answer 10

the number of observations in it

Question 11

in order to clearly define a statistical problem, we must…

Answer 11

we must first clearly state the population and the variables that it concerns

Question 12

exploratory data analysis

Answer 12

when you seek simply to describe datasets

Question 13

distribution

Answer 13

a description of the values a variable takes and how

often it takes them

Question 14

graph

Answer 14

a visual representation of a distribution

Question 15

count

Answer 15

a category’s size

Question 16

If we want to know the proportion of observations in a dataset that are in a given category…

Answer 16

we divide the count of that category by the sample size

Question 17

If we want to know the percentage of observations in a dataset that are in a given category…

Answer 17

we multiply the proportion of observations in the dataset that are in that category by 100%

Question 18

two ways we can look at the size of a given category

Answer 18

we might be interested in how it compares to either the sizes of the other categories, or in how it compares to the size of the population

Question 19

To compare the sizes of the categories with each other

Answer 19

we use a bar graph

Question 20

One drawback of bar graphs is

Answer 20

it is difficult to look at proportions of observations using them

Question 21

To compare the sizes of the categories with the size of the dataset

Answer 21

we calculate the percentage of the dataset that fall into each category

Question 22

to compare the percentage of any given category not only to each other, but… to the dataset as a whole as well

Answer 22

we use a pie chart

Question 23

roundoff error

Answer 23

when the error in percentage totals reflect the accumulated errors in rounding

Question 24

when dealing with quantitative data, we must have [blank]

Answer 24

a unit of measurement

Question 25

If we allow the value of a variable for a single individual to change, we must also allow [blank] for it to do so

Answer 25

time, on a time plot

Question 26

the long-term upward or downward movement

over time on a time plot

Answer 26

trend

Question 27

The amount of change over time in a time plot can be deceiving, so make sure that you [blank]

Answer 27

check the scale of the variable and where its values begin on the 𝑦-axis

Question 28

For small data sets, if we want to compare the values that a quantitative variable takes among different
individuals in a population, we can use a [blank]

Answer 28

stem plot (numbers in a column (“stem”) at left, other numbers stretching in rows to the right. you lop off the latter number on the stem and the former on the leaf

Question 29

In a stem plot, we reduce the digits in each observation to only the first digit, which we call a…

Answer 29

leaf (get it?). Ex. a score of 107 is represented by the 7 to the right of the 10 in the stem

Question 30

True or false: we NEVER include commas or decimal points in a stem plot

Answer 30

True

Question 31

For larger quantitative datasets, ranges into which the values of the data fall are called [blank]

Answer 31

bins

Question 32

When you make quantitative data categorical in bins, you can then make a bar graph called a [blank]

Answer 32

histogram

Question 33

we define statistics as…

Answer 33

the science of learning from data

Question 34

right-skewed or left-skewed

Answer 34

when data is further away from the center on one side than the other