Computing a Sample Mean
Computing a Sample Mean is a Grade 7 math skill in Reveal Math Accelerated, Unit 4: Sampling and Statistics, where students calculate the mean of a random sample by summing all values and dividing by the number of data points, then use this sample mean to make inferences about the population mean. The sample mean is the most common statistical measure of center.
Key Concepts
A sample mean is a statistic that represents the average of a subset of data drawn from a larger population. It is calculated by adding all the data values in the sample and dividing by the total number of values in that sample.
$$\text{Sample Mean} = \frac{\text{Sum of sample values}}{\text{Number of values in the sample}}$$.
Common Questions
How do you compute a sample mean?
Add all values in the sample together, then divide by the number of values. For example, the mean of the sample 4, 7, 9, 6, 4 is (4 + 7 + 9 + 6 + 4) / 5 = 30 / 5 = 6.
Why is the sample mean used to estimate the population mean?
The sample mean is an unbiased estimator — on average, it equals the true population mean. When we cannot measure every individual in a population, the sample mean provides a practical approximation.
How does sample size affect the accuracy of the sample mean?
Larger samples produce sample means that are closer to the true population mean because they are less affected by random variation. Smaller samples are more variable and less reliable.
What is Reveal Math Accelerated Unit 4 about?
Unit 4 covers Sampling and Statistics, including how to select random samples, compute sample statistics (mean, percent), compare distributions, and draw inferences about populations.