# Statistics Lectures - 19

A series of free Statistics Lectures with examples & solutions in videos.

These lectures discuss effect size, power, statistical versus practical significance and independent and dependent samples.

This is page nineteen of the series of free video lessons, "Statistics Lectures".

### Statistics - Lecture 55

Effect Size
The effect size is a measure of the strength of an effect.
After running a statistical analysis, if you reject the null hypothesis it then makes sense to calculate the effect size to determine the strength of the effect.

### Statistics - Lecture 56

Power
Power is the probability of correctly rejecting the null hypothesis.
Beta is the probability of incorrectly rejecting the null hypothesis.

### Statistics - Lecture 57

Statistical vs. Practical Significance
To reject the null hypothesis is to say that you have found Statistical Significance.

### Statistics - Lecture 58

Independent and Dependent Samples
One-Sample Methods
One sample z-test
One sample z-test for Proportions
One sample t-test
In these tests, one sample was being compared to the population.
Two-Sample Methods
Samples are compared to other samples.
Samples are independent if members of one sample are unrelated to members of the other sample.
Samples are dependent if the members are related.

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