# Statistics Lectures - 16

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

These lectures discuss parameters, statistics, sampling error, distribution of the sample mean and introduce the Central Limit Theorem.

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

### Statistics - Lecture 45

Sample Proportions
Example:
In a sample of 500 individuals, 75 are left handed. Describe the distribution of the sample proportion.

### Statistics - Lecture 46

Confidence Intervals about the Mean with Population Standard Deviation Known
The value of any statistic that estimates the value of a parameter is called a point estimate.
We rarely know if our point estimate is correct because it is merely an estimation of the actual value.
Example:
On the verbal section of the SAT, the standard deviation is known to be 100. A sample of 25 test-takers has a mean of 520. Construct a 95% confidence interval about the mean.

### Statistics - Lecture 47

Calculating Required Sample Size to Estimate Population Mean
We can calculate what sample size we will need in order to have a certain margin of error.
Example:
On the verbal section of the SAT, the standard deviation is known to be 100. What sample size would we need to construct a 95% confidence interval with a margin of error of 20?

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