Graphs

Question 1

Bar graphs

Answer 1

• a type of graph used to show the magnitude or freq of categories of the data
• data in each category are represented by vertical bars, with the length of the bars proportional to the magnitude or freq on a vertical y-axis

Question 2

box and whisker plot

Answer 2

• a type of graph that illustrates the distribution of values within a group through 5 numbers: minimum score, lower quartile, median Q2, upper quartile Q3 and maximum score
• outliers are shown as circles

Question 3

forest plot

Answer 3

• a type of graph used in a meta-analysis that shows the results of the individual studies as well as a cumulative summary of all studies
• the graph plots the point estimate of the measure of effect for each study as a square along a horizontal line, the width of which represents the confidence interval of the effect
• the area of each square is proportional to the study’s weight in the meta-analysis
• the measure of effect for all studied combined is plotted as a diamond
• the center of the diamond represents the point estimate for the cumulative effect and the width of the horizontal line represents the upper and lower confidence limits
• a vertical line represents is also known as a blobbogram

Question 4

histogram

Answer 4

• a graphical display of a freq distribution
• histograms display the distribution of data by plotting the freq of observations for each interval represented on the x-axis
• histograms use continuous bars of equal widths determined by the x-axis intervals, where bar height represents freq

Question 5

line graphs

Answer 5

• a graph that demonstrates the relationship between two or more quantitative variables
• line graphs usually are designed with the dependent variable on the y-axis and the independent variables on the x-axis and are ideal for showing trends in data over time. the data points are connected by curves

Question 6

scatter plots

Answer 6

a graphical display that illustrates the relationship between two quantitative variables. each paired (x/y) values is plotted on the graph as a single point
-a line of best fit generated mathematically may be fitted to the data to show the relationship among the variables

Question 7

stem and leaf plots

Answer 7

• a graphical display which enables the reader to observe the entire distribution of data without losing any information
• most commonly this is done by organizing data into categories and then dividing a number into two digits
• the first digit is placed to the left side of a vertical line and the second digit is placed on the right side of the vertical line