SCIE Data- Graphs and Plots

Bar Graphs

• Show comparisons between categories of data

Line Graph

• uses line segments to connect data points. ** MOSTLY USED: HOW DATA CHANGE OVER TIME

Pie Chart

• circle is divided into sections

• helpful when displaying the relative distribution of data in each category.

Dot Plots

• uses dots to show the number of data points in a group of data

• used for quantitative data

• helpful for identifying the mode, the shape or skew of the graph, and potential outliers on a dot plot

Stem plot

• each data value is split into a "leaf" (usually the last digit) and a "stem" (the other digits)

• best show clusters and gaps in the data

Histogram

• groups data into equal ranges and then plots the frequency of data in the ranges as bars

• used to summarize information from large sets of data

Box Plot

• uses a box and whiskers to display data

• based on five numbers: the minimum, the maximum, the first quartile, the third quartile, and the median of the data

Choosing a Graph or Plot

Graph Name	Data Type	Best Used For:
Bar Graph	Categorical	Comparisons
Pie Chart	Categorical	Percentages
Line Graph	Quantitative	Changes over time
Dot Plot	Quantitative	Small amounts of data
Stem-and-Leaf Plot	Quantitative	Small amounts of data
Box Plot	Quantitative	Large amounts of data
Histogram	Quantitative	Large amounts of data

EX1 A Physical Education teacher made a data table of the performance requirements to pass the Presidential Fitness Test along with a student's performance on the test. Which type of chart is best for the data set below?

Activity	Performance Requirements	Student Results
Curl Ups	50	58
Pull-ups	6	4
Sit-ups	31	28

Categorical data, therefore a double bar graph is best for this data set, as shown below. Using the double bar graph

Example 2: The following data shows the temperature forecast for each hour of a particular day in August. Which type of chart is best for this data set?

Time	Temperature °F
9:00 a.m.	70
10:00	75
11:00	80
12:00	86
1:00 p.m.	88
2:00	90
3:00	90
4:00	90
5:00	90
6:00	89

Quantitative because it shows numerical values. The data shows how the temperature changes with time. Therefore, a line graph is best for this data set, as shown below.

Example 3: During an obesity research project, a health worker categorized the weights of all incoming male freshmen at a certain university. The statistics associated with the data are presented in the table below. Which type of chart is best for this data set?

Weight Statistics on Male Freshmen (lbs)
First Quartile	159
Second Quartile	171
Third Quartile	205
Minimum	127
Maximum	335

Quantitative because weights is in numbers.

This data includes statistical values, such as the quartiles, associated with large amounts of data, therefore a box plot is the best for this data, as shown below.

Precision

• how close different measurements are to one another

Accuracy

• how close measurements are to a true value