PSSA Coach Lesson 28 Measures of Central Tendency M11.E Unit 5: Data Analysis & Probability

Key Concepts Central Tendency: ◦ The degree of clustering of the values of a statistical distribution that is usually measured by the arithmetic mean, mode, or median  Mean- Average  Median- Middle Value (after data is placed in ascending order)  Mode- Most frequent valued (duplicates are allowed) ◦ Also, includes the range and standard deviation of values  Range- Greatest Value – Least Value

Example 1 Test Scores: 78, 98, 45, 67, 82, 81, 93, 62, 73, 82 ◦ Find the Measure of Central Tendency of the following data:  Mean: _______________________  Median: ______________________  Mode: _______________________  Find the Range: _______________________

Key Concepts Standard Deviation: ◦ Otherwise know as the “statistical measure of dispersion”: a statistical measure of the amount by which a set of values differs from the arithmetical mean, equal to the square root of the mean of the differences' squares

WHAT DOES THAT CRAZY FORMULA MEAN??????????? Put simply we must find the sum of the all values minus the mean. Then, square root of that answer’s quantity divided by the mean.

Let’s try it…. (Write this down!!) Given the following temperatures, find the standard deviation. 33, 27, 35, 32, 21 Step 1: Find the mean. ◦ Mean: __________________ Step 2: Set up the equation replacing the variables with the values minus the mean. Set 3: Square Root the (answer in step 2 divided by the mean). THIS IS WHAT MS. ROBINSON CALLS TEDIOUS!!!!!! But valuable for some…

DO it on your own… Given the following data, find the mean, median, mode, range, and standard deviation: 45, 67, 81, 63, 67, 81 ◦ Mean: ____________ ◦ Median: ___________ ◦ Mode: ____________ ◦ Range: ____________ ◦ Standard Deviation: ________________

Now Do… Do Lesson 28 Practice on Pgs #1-10 all ◦ SHOW ALL WORK!!!! NO WORK = NO CREDIT ◦ For the open-ended: Write your response and justify the for answer with a sentence!!!