Lecture 5

percentage increase

When examining the change in the price or value of an item over time, plotting the actual increase can be misleading. It is often better to plot the____ from the previous period.

Bar graphs

compare several quantities by means of the differing heights of bars that represent the quantities. Our eyes react to the area of the bars as well as to their height.

A line

graph of a variable plots each observation against the time at which it was measured.

B. A bar graph

A better way to display the data found on the pie chart at the right is A. A line chart B. A bar graph C. Add more categories D. Make it more colorful

distribution

The ____ of a variable tells us what values it takes and how often it takes these values.

Chapter 10

Chapter 10

A.Categorical

Data was collected on car color frequencies for the students in a large introductory statistics course. What type of variable is "car color" A.Categorical B.Quantitative

B. Quantitative

Data was collected on the heights of students in a large introductory statistics course. • What type of variable is "height"? A.Categorical B. Quantitative

A.Fairly predictable levels over time

Dissolved oxygen (DO), an indicator of lake health, was measured at the bottom of Lake Murray in South Carolina. • What is the overall trend indicated in this graphic? A.Fairly predictable levels over time B. An upward trend over time C.A downward trend over time

C. Seasonal variation

Dissolved oxygen (DO), an indicator of lake health, was measured at the bottom of Lake Murray in South Carolina. • What is the predictable up and down pattern seen in this line graph called? A. Overall trend B. Striking deviations in overall trend C. Seasonal variation

overall pattern

First, look for an ____ . For example, a trend is a long-term upward or downward movement over time.

B. Time go on the horizontal axis

For a line graph, it is important that A. It be used for categorical data B. Time go on the horizontal axis C. No more than one line be on the graph D. Multiple lines should never cross

A. Equal width

It is important that the bars on a bar graph always be A. Equal width B. Vertical C. Horizontal D. Different colors

roundoff errors

It is not uncommon to see ____ in tables.

pictogram...

It is tempting to replace the bars with pictures and create a ____ .However, this can be misleading!

C. Striking deviations

Look how drastically the DO level varies the season before 2008. We need to investigate these A. Seasonal variations B. Overall trends C. Striking deviations

line graph

Many quantitative variables are measured at intervals over time. To display change over time, make a

deviations

Next, look for striking ____ from the overall pattern.

pie chart or a bar graph

To display the distribution of a categorical variable, use a

False:

True or False: : A pie chart can always show the data found on a bar chart.

True

True or False: A bar chart can always show the data found on a pie chart.

True

True or False: You do not need all the parts of a whole to create a pie chart as long as you create a category called "other".

B. Line Graph (with 2 lines - one for each group)

What other type of graphical display would have worked nicely to show how the age at first marriage changes over these years? A. 2 Pie Charts (college and non-college educated) B. Line Graph (with 2 lines - one for each group)

D.A bar chart

You have data comparing average SAT score across 7 different public universities. • A good choice for a graphical display would be A.A pictogram B. A line graph C.A pie chart D.A bar chart

C.Rounding to whole numbers

You notice the values on the pie chart at the right add to 99%. This is probably due to A.A calculation error B.Not having all the religious groups represented C.Rounding to whole numbers D.Processing errors

Pie charts and bar graphs

are most useful for the second kind of variable

A pie chart

can compare only parts of a whole.

Bar graphs

can compare quantities that are not parts of a whole.

a trend

is a long-term upward or downward movement over time.

a pie chart

is not as good a way to compare the sizes of the various parts of the whole.

A bar graph

makes it easier to compare categories.

A categorical variable

places an individual into one of several groups or categories.

errors. rounding down or round up

rounding numbers may have some

Pie charts

show how a whole is divided into parts.

A quantitative variable

takes numerical values for which arithmetic operations such as adding and averaging make sense.

seasonal variation

• Change over time often has a regular pattern of s that ____ repeats each year.