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1. Consider each of the above points for the table in Figure
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2. Comment on whether or not you think it meets each of the six points. Use complete sentences.
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2. Make a table like the one in Figure 2 only use data for just marijuana/hashish, cocaine, alcohol and cigarettes.
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3. Repeat exercise 2 only now instead of a vertical table, present data in horizontal form—putting the drug types across the top and the prevalences vertically at the side.
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4. Make a table like Figure 3 only use data for just marijuana, cocaine, alcohol and cigarettes.
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5. Using the following headings and the alcohol example, complete the following table for caffeine, cocaine, marijuana and nicotine.
(figure available in print form)
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6. Keep data on yourself for a week. Choose something like the number of cigarettes you smoke, number of calories you eat, how much you spend, or how many phone calls you make each day. Record your data in table form. We will use this data later to make bar and line graphs from it.
Graphs
A graph can be thought of as a drawn illustration that represents relationships between two or more things. Graphs may use dots, bars, lines, and/or other symbols to represent data. We will use a one dimensional graph—the time line, and several two dimensional graphs—the bar, line and
circle graphs.
Using
Time
Lines
A time line is a graph that shows (1) when things happen, (2) the order in which they happen and (3) the length of time between these events.
In developing any graph it is important to understand what is meant by the graph’s scale. It basically tells how much (years, percent, etc.) each unit represents. A scale is a comparison of two measurements. Let’s take an example. I want to make a time line that will roughly illustrate 7000 years of drug use. Figure 4. The line I want is to be 21 centimeters-so it will be as long as possible and still fit the required margins of the page. I’ll compare the two measures, 7000 years of drug history and 21 cm, then divide the top and bottom (numerator and denominator) by the same number until I get a scale or comparison that is easy to use.
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7000 yr
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=
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(dividing top and
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333.3 yr
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21 cm
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bottom by 21)
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1 cm
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That’s too hard to use. Dividing top and bottom by 7 I get
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7000 yr
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=
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100 yr
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21 cm
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3 cm
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That gives a scale I can easily use—every 3 cm represents 1000 yr.
To make a time line.
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1. Decide what dates you want to show.
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2. Decide about how long you want the line.
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3. Decide the scale you will use. So many units will represent so many rears.
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(figure available in print form)
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4. Draw line. Mark units.
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5. Label years and events.
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6. Title graph.
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7. Is it easy to read?
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8. Is it neat and attractive?
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9. Do I need a credit source for the data?
