Graphs in Biostatistics

Graphs in Biostatistics

1. Graphs in Biostatistics Prepared By: Shagufta Farooqui Department of Pharmacology Nanded Pharmacy College, Nanded

2. A graph, in the context of data representation and mathematics, refers to a visual representation of data points, values, or relationships between variables. Graphs are used to illustrate and analyze patterns, trends, and structures within datasets. They provide a visual way to convey complex information and make it easier for individuals to understand the underlying patterns in the data. There are various types of graphs Histogram, Bar graph Line graph Pie Chart, Cubic Graph, response surface plot, Counter Plot graph Graphs

3. Histogram What is Histogram? Ans :- Histogram is a graphical representation that is helpful to organize and display the data in more user-friendly format. Purpose: Representing the distribution of continuous variables . • Uses of Histogram 1. It helps in comparing process within specified limits . 2. It summaries large data. 3. It assists in decision making .

4. Histogram Uses: When  the data is continuous . When you want to represent the shape of the  data’s distribution . When you want to see whether the outputs of two or more processes are different. To summarize  large data sets  graphically. To communicate the data distribution quickly to others. Example: The histogram below represents per capita income for five age groups.

5. CLASS INTERVAL(PRICE RANGE OF PENS) 20-30 30-40 40-50 50-60 60-70 FREQUENCY(NUMB ER OF PENS) 15 20 30 25 35

6. Bar Graph A Bar Graph is a chart that uses either horizontal or vertical bars to show comparisons between categories Purpose: Displaying the distribution of categorical variables .

7. Advantages of Bar chart show each data category in a frequency distribution display relative numbers or proportions of multiple categories summarize a large data set in visual form estimate key values at a glance be easily understood due to widespread use in business and the media Disadvantages of Bar graph require additional explanation be easily manipulated to yield false impressions fail to reveal key assumptions, causes, effects, or patterns

8. Years 1989 1990 1991 1992 1993 Profit (million $$) 10 12 18 25 42

9. Multiple Bar Chart A multiple bar chart is used to represent distinct values for more than one item that share the same category Years 1989 1990 1991 1992 1993 Import 1000 1200 1800 2500 4200 Export 2000 4000 6000 8000 10000

10. A stacked bar chart is a type of bar chart that portrays the compositions and comparisons of several variables through time. Stacked charts usually represent a series of bars or columns stacked on top of one another. They are widely used to effectively portray comparisons of total values across several categories. S tacked bar chart DIVISION A B C NUMBER OF BOYS 30 25 15 NUMBER OF GIRLS 15 20 35 TOTAL NUMBER OF STUDENTS 45 45 50

11. Line Graph A line graph, also known as a line chart or a line plot, is commonly drawn to show information that changes over time. You can plot it by using several points linked by straight lines. It comprises two axes called the “x-axis” and the “y-axis“. The horizontal axis is called the x-axis.

12. Uses of line graphs: When you want  to show trends . For example, how house prices have increased over time. When you want  to make predictions  based on a data history over time. When  comparing  two or more different variables, situations, and information over a given period of time.

13. A pie chart (also called a Pie Graph or Circle Graph ) makes use of sectors in a circle. The angle of a sector is proportional to the frequency of the data. A pie chart is a good way of displaying data when you want to show how something is shared or divided. A pie chart, sometimes called a circle chart , is a way of summarizing a set of nominal data or displaying the different values of a given variable  (e.g. percentage distribution). This type of chart is a circle divided into a series of segments . Each segment represents a particular category. Pie-Chart

14. Advantages • Size of the circle can be made proportional to the total quantity it represents • Summarize a large data set in visual form • Be visually simpler than other types of graphs • Permit a visual check of the reasonableness or accuracy of calculations • Require minimal additional explanation • Be easily understood due to widespread use in business and the media Disadvantages • Do not easily reveal exact values. • Many pie charts may be needed to show changes over time • Fail to reveal key assumptions, causes, effects, or patterns • Be easily manipulated to yield false impressions

15. Cubic Graph In the mathematical field of graph theory, a cubic graph is a graph in which all vertices have degree three. In other words, a cubic graph is a 3- regular graph . Cubic graphs are also called trivalent graphs.

16. Response surface plot A response surface plot is a three-dimensional (3D ) graphical representation of the relationship between multiple independent variables (factors) and a response variable in experimental design and optimization. It is particularly used in the field of statistics, design of experiments, and engineering to visualize the interaction effects between factors and identify optimal conditions for a desired outcome.

17. Thank You