epidemiology

Demystifying statistics: Estimating sample size for a survey

Introduction Whether you want to understand people’s preferences for a product, estimate the proportion of people preferring a political party or estimate the prevalence of a disease in a population, you will need to calculate the number of respondents sufficient for your survey objective. How can you calculate this magic number? To obtain a completely accurate answer, you will have to ask each and every individual in your population. A population in statistics… Read More »Demystifying statistics: Estimating sample size for a survey

Descriptive Analysis: Take it easy!

INTRODUCTION A descriptive analysis is an important first step for conducting statistical analyses. It gives you an idea of the distribution of your data, helps you detect outliers and typos, and enable you identify associations among variables, thus making you ready to conduct further statistical analyses.  However, with availability of so many types of graphical and summary approaches, investigators get confused about which approach to use for analysis of their… Read More »Descriptive Analysis: Take it easy!

Conducting stratified analyses

INTRODUCTION Stratified analysis is a powerful statistical approach that allows you to test for confounding and interaction, but unlike logistic regression, it is quite simple and doesn’t distance you from your data. You can ‘see’ the associations and enjoy the insights gained from analysis. This approach is useful when you are interested in testing association between two categorical variables – say exposure and disease – by adjusting for a third categorical variable.… Read More »Conducting stratified analyses

Sample Size Calculations and Visualisations

Statulator is a free online statistical program that conducts statistical analyses, interprets the results and provides suggestions about reporting them. It can be accessed by clicking here. It includes a suite of sample size calculators for six scenarios: estimating a single proportion, comparing two independent proportions, comparing paired proportions, estimating a single mean, comparing two independent means and comparing paired means.  All sample size calculators provide live interpretations of the estimated sample sizes in plain English.… Read More »Sample Size Calculations and Visualisations