Unit 11: Unit 11: Biostatistics — Short Questions

Biostatistics is a branch of statistics that applies statistical methods to biological sciences. Biostatistics is essential for designing biological experiments, clinical trials, and epidemiological studies.

The median is the middle value of a data set when the values are arranged to ascending or descending order. If the number of values is odd, the median is the middle value. If the number of values is even, the median is the average of the two middle values.

Mean is calculated by adding all the values together and dividing the total by the number of values.

A bar chart is a graphical representation of data using bars of different heights or lengths.
Uses
It is used to compare the quantities of different categories. Bar charts are effective for comparing different categories and visually representing the distribution of data.

The mode is the value that appears most frequently in a data set. A data set may have one mode or more than one mode or no mode at all.
Steps to Calculate Mode
i. Count the frequency of each value in the data set.
ii. The value with the highest frequency is the mode.
Example 1
Consider the data set 150, 160, 165, 155, 160

• Frequencies 150 (1), 160 (2), 165 (1), 155 (1).
• The value with the highest frequency is 160. So the mode of the data set is 160.

(a) Designing biological experiments
(b) Chemical trials
(c) Epidemiological studies

Uses of Biostatistics
The major uses of biostatistics include:
1. Designing Experiments and Studies
Introduction
Biostatistics helps in planning and structuring experiments to ensure that the data collected will be relevant and sufficient to answer the research questions.
Example
For instance, in a clinical trial testing a new drug, biostatisticians determine the sample size needed to detect a significant effect.
2. Analyzing Biological Data
Introduction
Biostatistics involves applying statistical techniques to analyze data. This analysis can uncover trends, correlations and patterns.
Example
Analyzing the growth rates of plants under different environmental conditions can reveal how factors like light and water affect growth.

i. Epidemiology
Introduction
Epidemiologists use biostatistics to study the distribution and determinants of health and diseases in populations.
Example
Analyzing data on COVID -19 infection rates recovery rates and the effectiveness of vaccines involves biostatistics methods.
ii. Genetics
Introduction
Biostatistics is used to genetic research to analyze the inheritance of traits and the association of genetic variations with diseases.
Example
For instance, genetic studies use biostatistics to identify genetic markers linked to diseases like diabetes and cancer.

Steps to Calculate Median
i. Arrange the data in ascending order.
ii. If the number of values (n) is odd, the median is the value at the position (n+1)/2.
iii. If the number of values (n) is even, the median is the average of the values at positions (n/2) and (n/2+1).
Steps to Calculate Mode
i. Count the frequency of each value in the data set.
ii. The value with the highest frequency is the mode.

Steps to create a bar chart
i. Gather the data to be represented in the bar chart.
ii. Arrange the data into categories and their corresponding values.
iii. Draw a horizontal axis (x-axis) and a vertical axis (y-axis)
iv. Label the x-axis with the categories and the y-axis with the values.
v. Determine the scale for the y-axis based on the range of values in the data set. Divide the axis into equal intervals.
vi. For each category draw a bar with a height corresponding to its value. Ensure the bars are of equal width and are spaced evenly.
vii. Label each bar with its category name and value.