# Maths and Stats for Web Analytics and Conversion Optimization by Himanshu Sharma

Author:Himanshu Sharma
Language: eng
Format: mobi, epub
Published: 2015-10-23T14:00:00+00:00

Lesson 2: Statistical inference

Statistical inference (or statistical conclusion) is the process of drawing conclusion from the data which is subject to random variation.

Observational error is an example of statistical inference.

For example, consider the performance of three campaigns A, B and C in the last one month.

Here campaign B seems to have the highest conversion rate.

Does that mean, campaign B is performing better than campaign A and campaign C?

The answer is we do not know that for sure. This is because here we are assuming that campaign B has highest conversion rate only on the basis of our observation.

There could be an observational error. Our assumption could be wrong.

Observational error is the difference between the collected data and the actual data.

In order to minimize observational error, we need to segment the ecommerce conversion rate into visits and transactions: