# Statistics Lectures - 22

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

These lectures continues the discussion on samples t-test from the previous lectures.

This is page twenty-two of the series of free video lessons, "Statistics Lectures".

### Statistics - Lecture 66

Confidence Intervals for Dependent Samples t-Test
We use the Dependent Samples t-Test to test if two sample menas are different from one another.
After the t-Test, confidence intervals can then be constructed to estimate how large that mean difference is.

### Statistics - Lecture 67

Effect Size for Dependent Samples t-Test
The effect size allows us to measure the magnitude of mean differences.
This is usually calculated after rejecting the null hypothesis in a statistical test. If the null hypothesis is not rejected, effect size has little meaning.

### Statistics - Lecture 68

z-Test for Proportions, Two Samples
Researchers want to test the effectiveness of a new anti-anxiety medication. In clinical testing, 64 out of 200 people taking the medication report symptoms of anxiety. Of the people receiving a placebo, 92 out of 200 report symptoms of anxiety. Is the medication working any differently than the placebo? Test this clain using alpha = 0.05
1. Define Null and Alternative Hypotheses
2. State Alpha
3. State Decision Rule
4. Calculate Test Statistic
5. State Results
6. State Conclusion

### Statistics - Lecture 69

Confidence Intervals for the Difference of Two Proportions
We use the z-Test for Proportions to test if two proportions are different from one another.

Rotate to landscape screen format on a mobile phone or small tablet to use the Mathway widget, a free math problem solver that answers your questions with step-by-step explanations.

You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.