Statistics

Mean = average (sum of measurements/# of measurements) Range = spread of data (largest measurement –smallest measurement)

Standard deviation = how data is spread out around the mean -About 68% of data points lie within 1 standard deviation (+/-) of the mean -About 95% of data points lie within 2 SDs The smaller the standard deviation, the closer the data points are to the mean

T-test – used to compare two sets of data and determine if the differences between the two are significant (caused by experimental treatment rather than random chance) p = probability that chance alone could make the differences seen We generally look for a p value of 0.05 or lower, meaning there is at least a 95% chance that the difference is significant

Degrees of freedom – sum of the sample sizes - 2