Research Methods- Graphs Flashcards
Raw data table:
A record of individual data points collected from participants.
Frequency table:
A log of the number/frequency of observations of behavioural categories. Frequency tables are called tally charts.
Summary of descriptive statistics:
Patterns in large amounts of raw data can be hard to see in raw data tables and frequency tables.
Tables of descriptive statistics summarise large quantities of raw information and generally include measures of central tendency and dispersion.
Bar Chart:
Summarises the frequency of categorical/nominal data. This data is in distinct categories. The categorical variable (e.g. pet choice) belongs on the horizontal X-axis, and the frequency is on the Y-axis. The height of each bar is the frequency.
Bars in bar chart
THE BARS DO NOT TOUCH:
As the bars in a bar chart show categorical data, not continuous data, this is made clear by making sure each bar does not touch; if the bars touch, the graph is not a bar chart; it’s a histogram.
Bar charts
Displaying more than one variable:
Bar charts can display multiple variables (for example, showing two groups’ scores at two different time points). These bar charts should be clearly labelled/have a legend.
Pie Charts:
A circular graph, the full circle (360 degrees) represents all the data in the data set. Each wedge in the pie chart represents the proportion of one category that forms part of the data set. The size of each wedge section is proportional to the amount of that category in the entire data set.
Pie chart
Area:
The relative sizes of each category are clearly visible in a pie chart.
For example, a category with a value of 50% of the data set will make up half of the circle. A wedge half that size would be a quarter of the pie and 25% of the data set.
Scattergrams:
Display the relationship between two co-variables.
Each point plotted on the scattergram represents two measurements/variables of the same participant, and either variable can go on either of the axes.
Scattergrams
Correlational relationships:
Scattergrams visually display the (positive/negative/no) relationship between co-variables.
Scattergrmas
RS between Covariables
The strength of the relationships between covariables can also be judged visually, with stronger relationships showing data points clustering tighter along the line.
Histogram:
Displays the frequency of continuous numerical data. The frequency is placed on the Y-axis, and the continuous variable (e.g. test scores, age group, time scales, weight, height, income level) is on the X-axis.
Bars in Histogram
THE BARS DO TOUCH:
As the bars in a Histogram show continuous data, not categorical data, this is made clear by making sure each bar touches the next; if the bars don’t touch, the graph is not histogram; it’s a bar chart.
Line Graphs:
Also called a frequency polygon, line graphs allow for the display and comparison of two sets of continuous data on the same graph. The frequency is placed on the Y-axis, and the continuous variable is on the X-axis.
What type of graph do you need to draw for:
Categorical data / Nominal data =
Bar chart
