Summer Assignment

Question 1

individuals

Answer 1

objects described by a set of data

Question 2

variable

Answer 2

any characteristic of an individual

Question 3

categorical variable

Answer 3

places an individual into one of several groups or categories

Question 4

quantitative variable

Answer 4

takes numerical values where it makes sense to take an average

Question 5

distribution

Answer 5

tells us what values the variable takes and how often it takes those values

Question 6

discrete variables

Answer 6

a variable that cannot take on a value between its minimum and maximum value. Like flipping a coin; you can’t get 2.5 heads, only 2 or 3 heads

Question 7

Continuous variables

Answer 7

opposite of discrete variables. Can take on any value between minimum and maximum value

Question 8

Univariate Data

Answer 8

when you conduct a study that only looks at one variable; data that only contains one variable

Question 9

Bivariate Data

Answer 9

data that contains two variables and examines the relationship between them. For example, height and weight.

Question 10

Census

Answer 10

a study that obtains data from every member of a population. In most studies, a census is not practical, because of the cost and/or time required

Question 11

Boxplot

Answer 11

Also known as box and whisker plot. A boxplot splits the data set into quartiles.

Question 12

Bar Graph

Answer 12

A bar chart or bar graph is a chart or graph that presents categorical data with rectangular bars with heights or lengths proportional to the values that they represent.

Question 13

Conditional

Answer 13

The conditional probability of an event B is the probability that the event will occur given the knowledge that an event A has already occurred.

Question 14

Sample

Answer 14

a set of observations drawn from a population.

Question 15

Population

Answer 15

population refers to the total set of observations that can be made

Question 16

Inference

Answer 16

Statistical inference is the process of using data analysis to deduce properties of an underlying distribution of probability

Question 17

Frequency Table

Answer 17

When a table shows frequency counts for a categorical variable, it is called a frequency table

Question 18

Relative Frequency

Answer 18

To compute relative frequency, one obtains a frequency count for the total population and a frequency count for a subgroup of the population. The relative frequency for the subgroup is:

Relative frequency = Subgroup count / Total count

Question 19

Table

Answer 19

an arrangement of data in rows and columns, or possibly in a more complex structure.

Question 20

Interquartile Range

Answer 20

a measure of variability based on dividing a data set into quartiles.

Question 21

Five-Number

Answer 21

A five-number summary consists of five values: the most extreme values in the data set (the maximum and minimum values), the lower and upper quartiles, and the median

Question 22

summary

Answer 22

The information that gives a quick and simple description of the data

Question 23

Standard Deviation

Answer 23

The standard deviation is the square root of the variance. Its symbol is the greek letter sigma

Question 24

Variance

Answer 24

The variance is the average of the squared differences from the Mean. It is a numerical value used to indicate how widely individuals in a group vary. If individual observations vary greatly from the group mean, the variance is big; and vice versa.

Question 25

Roundoff Error

Answer 25

the difference between a rounded number and the actual value.

Question 26

Pie Chart

Answer 26

A pie chart (or a circle chart) is a circular statistical graphic, which is divided into slices to illustrate numerical proportion. In a pie chart, the arc length of each slice (and consequently its central angle and area), is proportional to the quantity it represents.

Question 27

Two-Way Table

Answer 27

A two-way table of counts organizes data about two categorical variables. Values of the row variable label the rows that run across the table, and values of the column variable label the columns that run down the table

Question 28

Marginal Distribution

Answer 28

This is a distribution of one of the variables. These are the counts or percentages found in the last row or column of the table or margins.

Question 29

Distribution

Answer 29

is a listing or function showing all the possible values (or intervals) of the data and how often they occur

Question 30

Segmented Bar Graph

Answer 30

In this graph each bar is a whole and is divided proportionally based on the conditional distributions for each variable. (2 variables, 1 for bar and one for the segments of the bar)

Question 31

Side-by-side Bar

Answer 31

like the segmented bar graph but the segments are placed next to each other instead of on top of each other.

Question 32

graph

Answer 32

A graph is a picture that represents data in an organized manner.

Question 33

Association

Answer 33

any relationship between two measured quantities that renders them statistically dependent.

Question 34

Simpson’s Paradox

Answer 34

an effect that occurs when the marginal association between two categorical variables is qualitatively different from the partial association between the same two variables after controlling for one or more other variables.

Question 35

Dotplot

Answer 35

a type of graphic display used to compare frequency counts within categories or groups.

Question 36

Shape

Answer 36

The shape of a distribution is described by its number of peaks and by its possession of symmetry, its tendency to skew, or its uniformity

Question 37

Mode

Answer 37

The mode of a set of data values is the value that appears most often.

Question 38

Center

Answer 38

The center of data is a single number that summarizes the entire data set. It is important to use the correct method for finding the center of data so you can accurately summarize the data set. You can do this by using either the mean or the median.

Question 39

spread

Answer 39

dispersion (also called variability, scatter, or spread) is the extent to which a distribution is stretched or squeezed. Common examples of measures of statistical dispersion are the variance, standard deviation, and interquartile range.

Question 40

Range

Answer 40

lowest value to highest value difference

Question 41

Outlier

Answer 41

a data point that differs significantly from other observations.

Question 42

Symmetric

Answer 42

data set split down the center is equal

Question 43

Skewed Right

Answer 43

the mean is typically greater than the median

Question 44

Skewed Left

Answer 44

the mean is typically smaller than the median

Question 45

Unimodal

Answer 45

a distribution with one clear peak or most frequent value

Question 46

Bimodal

Answer 46

a probability distribution with two different modes. These appear as distinct peaks

Question 47

Multimodal

Answer 47

many different modes or peaks

Question 48

Stemplot

Answer 48

also known as stem and leaf plot. a way of comparing data.

Question 49

Splitting Stems

Answer 49

when the leaves on the stem and leaf plot get too crowded you can split the stems into two different components, like 0-4 and 5-9 instead of 0-9.

Question 50

Back-to-back Stem

Answer 50

compare 2 populations by having the stem in the middle and the 2 populations back to back against the stem. Easy to compare

Question 51

Plots

Answer 51

how people display their data so it is easy to compare. EX: box plots, stem and leaf plots, scatterplots, etc.

Question 52

Histogram

Answer 52

bar graph-like representation of data that buckets a range of outcomes into columns along the x-axis

Question 53

Mean

Answer 53

average. add all numbers together then divide by number of data points to get the mean

Question 54

median

Answer 54

the middle number of the data set