Chapter 10

bar charts and pie charts are most useful for what kind of variables?

Bar charts and pie charts are most useful for categorical variables.

What type of graph do we use to show how quantitative variables change over time?

A line graph shows how quantitative variables change over time.

When making a data table, is it better to present data as counts or as rates?

It is better to present the data as rates, because they are more informative to someone reading the data table.

What type of error do we commonly see in data tables?

One error we commonly see in data tables is roundoff error.

what three things are necessary for a clear data table?

a main heading giving the subject and the date of the data, labels within the table to identify the variables and the nits they are measure in, and the sources of the data.

What are some of the disadvantages of using a pie chart? What about pie charts makes them hard for people to visually read?

Pie charts are hard to draw by hand, have no natural way to order them and can be hard to compare the sizes of the different categories. It is harder for us to visually compare angles then lengths, so it is hard for people to visually read a pie chart. One way to help make a pie chart easier to read is it add the percentages falling into each category next to the wedge representing that category.

What are pie charts used to show? What do wedged within the pie chart represent?

Pie charts are used to show how a whole is divided into parts. The entire circle represents the whole and the wedges within the pie chart represent the parts. The size of the pie chart represents what portion of the whole fall into category.

What is the distribution of a variable?

The distribution of a variable tells us what values it takes and how often it takes those values.

what chart makes it easier to us to compare categories? What are some advantages of this type of chart?

Bar graphs make it easiest for us to compare categories. These are easy to draw, there is a natural way to order categories with a bar graph, and we can visually compare different categories, even those not positionally next to each other.

Why do we use data tables?

Data tables are used to summarize large amounts of information. We use them to show us what is going on with the data overall, instead of what is going on with each individual.