Test 2

Question 1

A ____ is a graph for a quantitative variable

Answer 1

Histogram

Question 2

______ are like histograms, but they also give the individual values.

Answer 2

Stem and Leaf

Question 3

We describe the ______ of a distribution in terms of its modes, its symmetry, and whether it has any gaps or outlying values.

Answer 3

shape

Question 4

Peaks or humps seen in a histogram are called the ____ of a distribution

Answer 4

modes

Question 5

A distribution whose histogram has one main peak is called ?

Answer 5

unimodal

Question 6

two peaks?

Answer 6

bimodal

Question 7

three or more peaks?

Answer 7

multimodal

Question 8

A distribution whose histogram doesn’t appear to have any mode and in which all the bars are approximately the same height is called _______.

Answer 8

Uniform

Question 9

A distribution is _______ if the halves on either side of the center look, at least approximately, like mirror images.

Answer 9

symmetric

Question 10

The thinner ends of a distribution are called the ____?

Answer 10

Tails

Question 11

If one tail stretches out farther than the other, the distribution is said to be _____ to the side of the longer tail.

Answer 11

skewed

Question 12

The ______ are the values that frame the middle 50% of the data.

Answer 12

quartiles

Question 13

The ____ is defined to be the difference between the two quartile values.

Answer 13

interquartile range (IQR)
IQR = Q3 - Q1

Question 14

The ______ of a distribution reports its median, quartiles, and extremes (maximum and minimum).

Answer 14

five-number summary

Question 15

Once we have a five-number summary of a variable, we can display that information in a _______?

Answer 15

box plot

Question 16

Histograms work well for comparing two groups, but _____ offer better results for side-by-side comparison of several groups.

Answer 16

box plots

Question 17

A display of values against time is sometimes called a _______.

Answer 17

time series plot

Question 18

_____ may be drawn with the points connected

Answer 18

Time series plots

Question 19

______ often show a great deal of point-to-point variation, but general patterns do emerge from the plot.

Answer 19

Time series plots

Question 20

To better understanding the trend of times series data, plot a _______.

Answer 20

smooth trace
(A trace is typically created using a statistics software package and will be discussed in a later section)

Question 21

When a ____ is stationary (without a strong trend or change in variability), then a histogram can provide a useful summary.

Answer 21

time series

Question 22

A ______ distribution has roughly the same shape reflected around the center

Answer 22

symmetric

Question 23

_____ are values that lie far from the rest of the data.

Answer 23

outliers

Question 24

The _____ is the middle value; half the values are above and half are below the median. It is a better summary when the distribution is skewed or has outliers.

Answer 24

median

Question 25

The ______ is roughly the square root of the average squared difference between each data value and the mean. It is the summary of choice for the spread of unimodal, symmetric variables.

Answer 25

standard deviation

Question 26

The _____ is the difference between the quartiles. It is often a better summary of spread for skewed distributions or data with outliers.

Answer 26

IQR

Question 27

We standardize by finding ______. To convert a data value to its z-score, subtract the mean and divide by the standard deviation.

Answer 27

z-scores

Question 28

_____ have no units, so they can be compared to z-scores of other variables.

Answer 28

z - scores