Analysis of Data

In writing your lab report, when it comes to the point where you need to analyze your data:

1. Please show any formulas you use.

2. Show one example (using your data) of how to perform the calculations for each formula.

#### Noting Precision of Measurement

Statistics:

Reporting Uncertainty in Measured Data: Data is often hard to collect consistently in the same manner, so there is some inherent uncertainty when reporting data. Reporting such uncertainty helps the viewer interpret how accurate the results are, and may help determine whether the data supports the hypothesis or not.

Average/ Mean: Add each of the numbers within a data set and divide by the number of numbers in the data set.

Range: The range reports the difference between the minimum and maximum numbers of a data set.

Percent Change: Used to determine amount of change from beginning to end. Useful in comparing different data sets where the starting numbers (or total numbers) are not the same.

Rate of Change (Slope of line on Graph) : Determining the slope of the line of a graph helps tell us how one factor ( y-axis) changes in relation to another (x-axis). If the x-axis is time, this change becomes rate of change.

Standard Deviation: A measure of the average amount the data deviates from the average of the data set. Often used to determine whether a conclusion that compares 2 sets of data is valid.

Coefficient of Variance: Useful in comparing the accuracy of a set of tests or trials. Essentially it allows us to convert standard deviation to a percent which then more accurately compares the S.D. to the average of the data set. This is especially useful if your S.D is small, but your average is also small.

Correlation Coefficient: Used to determine how closely two different sets of data correlate (Ex: DO & Temp.)

Percent Deviation: Used to calculate how accurate student determined data is by comparing it to a known standard or to values determined by an established government lab! This is for Quality Control purposes!

Slichter