Graphs, Tables, and Charts a how to guide

Making Data Tables and Graphs An experiment shows the effect of fertilizer on the mass of tomatoes, with the observation that Fertilizer X produces a higher mass in tomatoes than other brands of fertilizer. How is the data communicated and what does it mean?

What do you include in tables and graphs? Data entry into a table should be neat and legible with 2 or more columns/rows Descriptive title (how the Independent Variable affects the Dependent Variable) Independent Variable in the first column/row with unit in parentheses Dependent Variable in the second column/row with unit in parentheses Data collected in ordered pairs/coordinates (two pieces of data that are directly related to each other)

Making a Table The Effect of Fertilizer on the Mass of Tomatoes Title FertilizerMass of Tomatoes (g) W210 X275 Y235 Z200 Dependent Variable (unit) Dependent Variable (unit) Independent Variable (unit) Ordered Pairs

Making a Table Data on the previous slide showed only one tomato plant’s growth REMEMBER: there should be at least 3 trials for the experiment to be more accurate. The table can also show the average of each experimental group and the control group. When typing, make sure the table is on one page. If it continues to the next page, you must label with the title and column/row headings again.

Making a Table For Example: (Dependent Variable) Ordered Pairs The Effect of Fertilizer on the Mass of Tomatoes Title to reflect relationship between dependent and independent variable (Independent Variable)

Now we can graph Data is in a table, and can now be moved into a graph. A graph will show trends and patterns in the data.

What kind of graph do I need? Bar Graph – use when ordered pairs are compared that are discrete, such as brand of paper towel. number vs name The independent variable is all text or numbers representing text (i.e. sample 1, sample 2) The independent variable is not a measurement (i.e. green, blue, yellow)

What kind of graph do I need? Line Graph – use when different measurements of the same item are recorded over time (continuous) number vs number Time Temperature

What kind of graph do I need? In both bar and line graphs, the independent variable and unit are located on the X axis; the dependent variable and unit are located on the Y vertical axis. MIX DRY Remember this clue: DRY (Dependent Responding Y axis) MIX (Manipulated Independent X axis)

This graph shows 3 trials Trial 2Trial 1Trial 3

This graph shows the average of the three trials

Line Graph Example: The data in the next graph was collected on plant growth over a seven month period. The height of the plants was measured in centimeters.

Line Graph Example: Plant Growth Over Time Independent Variable Dependent Variable

Line Graph Example:

Line Graph Rules: Refer to the Graphing Handout. When in doubt, use a line graph. Label each axis, give units. All graphs have an origin of (0,0) You may use a “squiggle” to indicate a break in the number sequencing. Never graph across this.

Line Graph Rules: Extrapolated (hypothesized) points are indicated differently from measured point. Extrapolated points are hollow Interpolated (measured) points are solid Extrapolation: Use dotted line on the extension of your life beyond the measured points on graph.

Line Graph Rules: If data has linear progression, use “best fit line,” otherwise, “connect the dots.” Do NOT draw both!

What kind of graph do I need? Pie Chart – use when pieces of a whole are shown % adds to 100

Determine the total number Find the % of each piece of data Independent Variable Dependent Variable Percentage of Species of Whales

Pie Chart In this case the percentage of certain types of whales is shown. Does a percentage have to be determined to make this comparison with this data?

Pie Chart This graph shows the whale data based on their numbers and not percent of the population.

What’s wrong with this graph?

Which is easier to read?

Let’s Review A student experimented to find out how table salt affects the freezing point of water. After cooling distilled water with ice, the temperature was measured and recorded. Several more measurements were taken in regular intervals after specific amounts of table salt were added. Which data table is best constructed to represent this data? Title Water + Salt (g) Temp. ( o C) Title Water + Salt Temp Title (g)( o C) ABC D Title Temp. ( o C) Water+ Salt (g)

Let’s Review Title Water + Salt (g) Temp. ( o C) Title Water + Salt Temp Title (g)( o C) ABCD Title Temp. ( o C) Water+ Salt (g) Table A has all the correct components of independent variable on the left column and dependent variable in the right. A title is given and the units are provided in the column heading. Table B shows independent and dependent variables at incorrect positions. Table C does not include units in the column descriptions. Table D does not describe the variables

Let’s Review A student experimented to find out how table salt affects the freezing point of water. After cooling.5 L of distilled water with ice, the temperature was measured and recorded. Several more measurements were taken in regular intervals after specific amounts of table salt in grams were added. When graphing the results of this procedure, which variable should the students place on the Y axis? A. freezing point of water B. grams of salt added to the ice C. the amount of ice added to the water D. temperature of the water

Let’s Review Answer D A. freezing point of water The temperature of the water only at freezing point shows only one data point and neglects data read to that point. B. grams of salt added to the ice This is the independent variable which is located on the X axis. C.the amount of ice added to the water This would not be a factor to be graphed. D.temperature of the water This is the dependent variable which is placed on the Y axis. The temperature of the water changes in response to the addition of salt.

Let’s Review A beaker with 250 mL of water was left in a window where sunlight entered. The temperature of the water was measured with a sensor every 2 minutes in a 45 minute period. The rate at which the water temperature rose was then determined. In what kind of graph would the data best be displayed? A. Bar graph B. Line graph C. Pie chart D. Pictograph

Let’s Review Answer B A.Bar graph a bar graph is used with data is discrete and may be descriptive, such as type of paper towel. B. Line graph C. Pie chart A pie chart is used when comparing numbers or percentages of items. D. Pictograph A pictograph is used with actual images or pictures of items. The data is continuous for both dependent and independent variables, making only a line graph appropriate to illustrate this data. Both time and temperature are measured continuously throughout the data collection of the water temperature.

Let’s Review This graph shows information for a specific date, Dec. 15, over a period of 8 years. Is this data best illustrated in a line graph? A.Yes because both dependent and independent variables contain discrete data. B.Yes the data between points are continuous and have meaning. C.No because the data would be better shown with a pie graph. D.A bar graph would be better because it is easily constructed with this data.

Let’s Review A.Yes because both dependent and Independent variables contain discrete data. The dependent variable, temperature is continuous data. B.Yes the data between points is continuous and has meaning. This is the correct answer. C.No because the data would be better shown with a pie graph. This data does not show a percent or number that can be illustrated in a pie graph. D.A bar graph would be better because it is easily constructed with this data. The ease of graph construction should not be considered in the type of graph that best illustrates the data. Answer B

Let’s Review Lupe needed to know the composition of soil in her flowerbed before deciding what to plant based on the information. She sent the soil to an agricultural extension service to get the results. The report showed that the soil contained 5% organic, 10% clay, 3% sand, 45% mineral, 20% air, and 17% gravel. What type of graph best illustrates this information? A.Bar graph B.Double line graph C.Line graph D.Pie chart

Let’s Review Answer D Dependent and independent variables are not found in this type of information. Only a pie chart would be appropriate. A pie chart easily illustrates percentages in data.