How to do Statistics on your 3rd Year Project

• Study conceptual issues and let ideas form
• Convert ideas into questions
• Look for biological system to work with - positives and negatives
• Develop a testable hypothesis - both null and alternative
• Design data collection to test hypothesis
  • Try to keep other variables constant
  • Use maps to locate sampling sites
  • Imagine what data will look like
  • Descriptive data - use stratified random sampling to control extaneous variation
  • Use a control to test effects of manipulation
  • Don't be afraid to think idealistically - can make informed compromises
• Decide on appropriate stats
• Construct a statistical model
• Work out how much data you need to test the hypothesis
  • In general need at least 6 error degrees of freedom to have any power
• Begin collecting data

Differences and chance cause variation
No measurement is exact
Bias is rife
Bigger is usually better for sample size
Correlation does not imply causation
Regression to the mean can be mislead
Extrapolating beyond the data is risky
Beware of the base-rate - the ability of an imperfect test to identify a condition depends upon the likelihood of that condition occurring (the base rate)
Controls are important
Randomization avoids bias
Seek replication, not pseudoreplication
Scientists are human
Significance is significant 
Seperate no effect from non-significance
Effect size matters
Study relevance limits generalizations
Feelings influence risk perception
Dependencies change risks
Data can be dredged or cherry picked
Extreme measurements may mislead