Do Now

1. Get a copy of the data that you got during the lab on Thursday/Friday. Complete any and all calculations that are required by your lab.

Why Statistics Matters!

Statistics• Statistics is the study of

the collection, organization, analysis, and interpretation of data

• How do you know if data is good or not?

• Statistics allows for us to call data good or bad!

Calculating an Average

• An average is a measure of the overall data.

• Gives the value that the data tends towards the middle.

Problems with an Average

• Averages can hide just how bad your data is.

• Averages also can make your data look worse than it actually is

Calculating Standard Deviation

• A standard deviation tells us how much variance exists within an average.

• This will tell your reader if the average accurately reflects the data or if it is lying to you.

Class Example

• You have the following data and average. Calculate the standard deviation.

Trial Speed (m/s)

1 20

2 30

3 30

4 35

Average 28.75

Table Talk

• You have the following data and average. Calculate the standard deviation

Trial Speed (m/s)

1 5

2 5

3 10

4 20

Average 10

Why is a Standard Deviation Important?

• Tells us the reliability of our data

• A huge standard deviation tells the reader that even if the average is close to the actual value, that the actual data is not reliable.

• A small standard deviation tells the reader that you had very precise data.

Calculate Average and SD

• Go to your data and calculate the average and standard deviation (if necessary).

• If you only ran one trial, than complete any other calculations you may have not already finished.

• NOTE – Everyone must have a standard deviation present when reporting averages.

Pick experiment

Research Topic

Develop Procedure

Compare Your

Procedure to Book

Develop 2nd Procedure to Minimize Experimental Error

1st Run Through of Lab

Calculations and Analyze Data

Develop 3rd Procedure to Minimize Experimental Error

2nd Run Through of Lab

Calculations and

Analyze 2nd Data

Write Discussion

and Introducti

on

Make Poster for Presentati

on!

1 2 3 4

5678

9 10 11 12

Closing Time

• Turn in final results, tables, and statistics before leaving.