1. Measures of Central Tendency & Center of Spread

2. Minimum & Maximum
Minimum: The smallest number in a data set.
Maximum: The biggest number in a data set.
Example: What is the minimum and maximum of the data set.
9, 3, 2, 7, 12, 5, 6, 6, 8

3. Mean
Mean: Measures the center of the data and provides an average for the data set.
Calculated by adding up all of the numbers and dividing how many numbers there are in the data set.
Example: Calculate the mean. Round to the nearest tenth. 2, 3, 5, 6, 6, 7, 8, 9, 12

4. Median
Median— The middle value of a data set. Measures the center of the data. 
Put the numbers in order from least to greatest. Find the number that is in the center. If there are two numbers in the center, add the two numbers together and divide it by two.
Example: Find the median of the following numbers: 3, 7, 5, 6, 12, 6, 8, 2, 9, 3

5. Mode
Mode– Measures the center of the data. The number that appears the most.
Example: What is the mode of the following data set.
{2, 3, 5, 6, 6, 7, 7, 7, 8, 9, 12}

6. Lower Quartile, Upper Quartile, & IQR
Lower Quartile and Upper Quartile— Use the median to split the data into two. Do not include the median in either side of data. Find the median of each half. The median of the lower half is the lower quartile (Q1). The median of the upper half is the upper quartile (Q3).
Interquartile Range (IQR) ‐ The spread of the middle 50% of the data. Subtract the lower quartile from the upper quartile.
Example: Find Quartile 1, quartile 3, and IQR for the following data set: 2, 3, 5, 6, 6, 7, 8, 9, 12

7. Range
Range— The spread of the data. Subtract the minimum from the maximum.
Example: Use the following data to calculate the range.
{2, 3, 5, 6, 6, 7, 8, 9, 12}

8. You Try
Find the mean, median, mode, range, Q1, Q3, IQR for the following data set. {3, 8, 12, 5, 8, 7, 9, 10}

9. Mean Absolute Deviation
How to find the mean absolute deviation.
Step 1: Find the mean of the data.
Step 2: Find the positive (absolute value) differences between the mean and each data point.
Step 3: Find the mean of the differences.

10. Example
Find the MAD of 5, 9, 10, 4, 11

11. You Try
Find the MAD of 3, 12, 10, 14, 8