Statistic Tests -Module 4 Flashcards
Reason for selecting Standard deviation
This is a measure of spread in the data. This value gives an indication of the amount of spread
Reason for selecting student’s t-test
This looks for significant difference between two sets of data for one characteristic between two sub-groups
Reason for selecting spearmans rank correlation co-efficient
This looks for relationship between the data (mean) for two variables
Reason for selecting chi squared test
This looks for significant difference between observed results and what you might expect, where the data fits into categories
Example of standard deviation use
The effect of an environmental factor on a characteristic, e.g sunlight on plant height
Example of t-test
Comparing mean fruit weight for two crops grown in different fields
Example of spearmans rank
Height and width of limpets in a seashore
Example of use of chi-square test
Comparing results of an actual genetic cross with the predicted ratio
what do you do first before conducting a test
write hypthosies
How to evaluate method. What to talk about
-sample size
-repeats
-control experiments
-control variables
-Bias
-duration of experiment
What to mention when evaluating data
-state overall trend
-is there any overlap on data? E. G: SD bars
-is test group result different from control group result
-is there a statistic? What does it show?
What to consider when evaluating a conclusion
Consider both data and method
Use ALL information
nul hypothesis for t-test
This is a statement of what we would expect if there is no significant difference between two means, and that any differences seen are due to chance
degree of freedom formula t test
(n1 - 1) + (n2 - 1)
nul hypothesis for spearman rank
no correlation
