Types of Graphs and Data Presentation in Scientific Papers

Question 1

Qualitative Variables

Answer 1

Take values that cannot be ordered in a logical or natural way.
Eye color, body shape…

Question 2

Quantitative Variables

Answer 2

Represent measurable quantities. Take values that can be ordered in a logical and natural way.
Shoe size, house prices, weight, nr. of semesters studied.
Use mathematical formulas to draw conclusions.

Question 3

Graphs - What are they and their purpose

Answer 3

Diagrams representing two or more variables.
Show evidence. Provide clues that words and equations do not.
Great tool to form hypothesis and draw conclusions.
Can be inaccurately interpreted -> incorrect conclusion.

Question 4

Pie Chart

Answer 4

Visualize absolute and normal frequencies of nominal (categorical) and ordinal variables.

Question 5

Bar Chart

Answer 5

Visualize absolute and relative frequencies of observed values of a variable. Nominal or ordinal? variables.

Question 6

Histogram

Answer 6

Visualize distribution of values of continuous variables.

Question 7

Histogram vs Bar Chart

Answer 7

Distribution of variables (trendline) vs comparing variables.
Quantitative data (scale variables) vs categorical variables (nominal/counted)
Bars cannot be re-ordered vs Bars can be re-ordered

Question 8

Line Graphs

Answer 8

Visualize data collected over a specific topic and time interval. Data points represent the observations.

Question 9

Box Plots

Answer 9

Visualize distribution of data based on a 5 nr summary:
Lower extreme: Q1 - 1,5xIQR
Lower quartile Q1: Middle nr. between smallest value and median.
Median Q2: Middle value of data
Upper quartile Q3: Middle nr. between median and highest value.
Upper extreme: Q3 + 1,5xIQR
IQR: Q3-Q1
Corresponds to normal distribution.
U.E. and L.E. identify outliers.

Question 10

Scatter Plots

Answer 10

Visualize relationship between 2 quantitative (scale) variables measured on the same individuals. Can visually detect outliers.
Type of relationship -> tendency of increase /

Question 11

Tables

Answer 11

Present results from research, within or between group comparison or used to show participants’ demographic or clinical characteristics.

Question 12

Outliers

Answer 12

Represent a value distant from the rest due to variability or error. Doesn’t correspond to the statistics, we remove it.
Visualize them in scatter plots.
Tukey’s rule in box plots (calculate lower and upper extremes)