1. Measuring Variability
Algebra

2. I can use and understand standard deviation.
AIM
I can use and understand standard deviation.
TOPIC: Standard Deviation

3. DO NOW
Use your calculator to find the mean and median of the data set below. Which measure would better describe the data?

4. Interpreting Statistics
Sometimes it’s just as useful to measure the range of data as it is to know the “middle”
Variability: describes how large or small the range is of a given data set; how data varies
Some situations produce very high variability while others produce very small variability

5. Variability
Standard Deviation (σ): measures how spread out or condensed your data is
Large standard deviation: Spread out
Small standard deviation: Condensed data
You can use your calculator to find this value
Steps: STAT, , 1-Var Stats, σx
Using your data from the Do Now, what is the standard deviation of the age of these cars? Why?

7. Which brand of battery would you buy? Justify your answer.

8. 2. Why is the standard deviation such a large number?
1. Calculate the mean, median, and standard deviation of the given data set.
2. Why is the standard deviation such a large number?
3. If Coach Sauer were describing his athletes’ study habits to his boss, which measure (mean, median, standard deviation) do you think he would use? Why?

9. Which set of data has a larger standard deviation (σx)? Why?
EXIT TICKET
Which set of data has a larger standard deviation (σx)? Why?
Set A:
Set B: 10 12 11 9 7 6 22 21 24 26 8 20 4 25 34