A measure of variability that describes an average distance of every score from the mean-if standard deviation of two varibales do not overlap, there is a statistically significant difference
Why would you chose standard deviation over the range?
-shows spread of data rather than just highest or lowest-reduces effect of anomalies
What is better than standard deviation?
Students T test-judges the significance in the difference between two sample means
T values and P values
-if the T value is higher than the critical value then there is a statistically significant difference between the two variables. Reject the null hypothesis.-the P value should be less than 0.05 (as biology needs a 95% confidence level)
Null and alternative hypotheses
NullThere is not a statistically significant difference between variables x and y. Any difference is due to chance.AlternativeThere is a statistically significant difference between variables x and y. The difference is not due to chance.
