T-Interval (t statistics)

T interval is good for situations where the sample size is small and population standard deviation is unknown.

When the sample size comes to be very small (n≤30), the Z-interval for calculating confidence interval becomes less reliable estimate. And here the…

Statistical Power

Power is in the context of Statistical Testing, stands for a conditional probability of _REJECTING a FALSE HYPOTHESIS_.

“power -> power of justice -> ability to remove the bad one”

Truth World & Lies World

Significance Testing

Also called the Null Hypothesis Significance Testing.

We design a Significance Test to evaluate the strength of the evidence against some null hypothesis. 
The alternative hypothesis is the claim we are trying to find evidence in favor of.

Hypothesis Testing

Hypothesis Testing is that we make a assumption, or a hypothesis about something, and we then make a test and do statistic on it as evidence to against the hypothesis.

We can NEVER prove the null hypothesis, because “INNOCENT UNTIL PROVEN GUILTY”.

Testing Errors (Mistakes)

Type 𝐈 & Type 𝐈𝐈 Errors

Type I & Type II Errors are conditional…

Inference for comparison

Two-sample inference for the difference between groups

Conditions for Two-sample Z

“same-o same-o”.

The conditions we need for inference on two proportions are: