Warm Up Homework: Standard Deviation Worksheet

Guess What? You have another pop quiz!!!!!!!!!! I know you’re saying Yes! another good grade Or Yes this is my chance to make a good grade!!!!

Today’s Lesson: Standard Deviation April 25, 2014

Recall ……… What is the Measure of Dispersion?

Measures of Dispersion Another Measure of Dispersion is Standard Deviation Standard Deviation – is the measure of how the values in a data set vary, or deviate, from the mean.

Here is a formula for Standard Deviation

Finding the Mean and the Standard Deviation

Finding the Mean and the Standard Deviation Don’t get too bogged down about the weird looking formula. There are 5 steps that you need to take to find the standard deviation Let’s look at how they completed the table using the data from the example

Finding the Mean and the Standard Deviation X 𝒙 12.6 15.1 11.2 17.9 18.2 Step 1: Find the mean ( 𝒙 )

Finding the Mean and the Standard Deviation Step 2: Find the difference between each data value and the mean: (X - 𝑿 ) X 𝑿 X - 𝑿 12.6 15 15.1 11.2 17.9 18.2

Finding the Mean and the Standard Deviation X 𝑿 X - 𝑿 (X − 𝑿 ) 𝟐 12.6 15 -2.4 15.1 0.1 11.2 -3.8 17.9 2.9 18.2 3.2 Step 3: Square each difference: (X − 𝑿 ) 𝟐

Finding the Mean and the Standard Deviation Step 4: X 𝑿 X - 𝑿 (X − 𝑿 ) 𝟐 12.6 15 -2.4 5.76 15.1 0.1 0.01 11.2 -3.8 14.44 17.9 2.9 8.41 18.2 3.2 10.24

Finding the Mean and the Standard Deviation Step 5: Take the square root to find the standard deviation 𝐒𝐭𝐚𝐧𝐝𝐚𝐫𝐝 𝐃𝐞𝐯𝐢𝐚𝐭𝐢𝐨𝐧(𝝈)= __________

What does this mean?

You Try

Within how many standard deviations do all of the data values fall?

You Try

Since you were such wonderful angels today!!!!!! I will show you another method of doing this with your calculator!!!!!!

Using Your Calculator Let’s do a problem Step 1: Put your data in STAT (use STAT - - Edit) Step 2: Press STAT- - CALC- - 1-Var Stats (For the yellow calculators you will have to press calculate next) – everyone else just press enter again. Your answer is the one with the 𝐒𝐢𝐠𝐦𝐚(𝝈) Let’s do a problem

Let’s get started on our homework or finish our homework!!!! Happy Friday!!!! Let’s get started on our homework or finish our homework!!!!