Chapter 1: Exploring Data Lesson 3: Measures of Center Mrs. Parziale

Vocabulary Mean – ___________ of all values ____________ by the number of values. Finding the mean requires finding the sum of a data set. Median – the ____________ value for a set of data listed in increasing or decreasing order Mode – the value which occurs _________ ________ in a data set (does NOT always measure center, even though it is also listed as a measure of central tendency) Since both the mean and median are measures of central tendency, they are usually located in a cluster, however they are not always close together in that cluster. Sum divided middle most often

Sigma/Summation Notation: f 1 + f 2 + f 3 + … + f n = “i” refers to the INDEX – the location in the list of numbers is the Greek letter S for “sum” Bottom number is starting index/location in list Top number is finishing index/location in list

Example 1: Using the data from the “health club” example in lesson 2. 4, 6, 10, 7, 6, 11, 3, 6, 8, 7, 4, 6, 5, 6 What is f 1 ? What is f 2 ? What would n be in this example? What is f 14 ? Using sigma/summation notation, how would you indicate you want to add the first 6 numbers? What is the value of the first 6 numbers?

Example 1, cont. Using the data from the “health club” example in lesson 2. 4, 6, 10, 7, 6, 11, 3, 6, 8, 7, 4, 6, 5, 6 What is = ____________

4, 6, 10, 7, 6, 11, 3, 6, 8, 7, 4, 6, 5, 6 Mean = or What is the mean of the data set above? What is the median of the data set listed above? What is the mode of this data set? Example 1, cont.

Example 2: Given the following data set {1, 9, 2, 8, 3, 7, 4, 6, 5, 5} What is f 4 ? What is f 7 ? Find = _______ What is the mean? Median? Mode?

Closure What is “mean”? “median”? “mode”? What is the sigma notation used for? If a data set has 5, 3, 7, 8, 3 –Find the mean, median, mode –Find