statistical analysis bryan ng. pitfalls to avoid complex analysis and big words impress people....
TRANSCRIPT
Statistical analysis
Bryan NG
Pitfalls to avoid• Complex analysis and big words impress people.
• Analysis comes at the end when there is data to analyze.
• Data have their own meaning
• Stating limitations weakens the evaluation.
A six step guide to statistical analysis• Think about analysis EARLY• Start with a plan• Code, enter, clean• Analyse• Interpret• Reflect−What did we learn?−What conclusions can we draw?−What are our recommendations?−What are the limitations of our analysis?− Is this the clearest way of presenting out message?
Why plan
• To make sure the questions and your data collection instrument will get the information you want
• Think about your “report” when you are designing your data collection instruments
• Statistical tests are only valid if planned in advance• Helps you find out your own assumptions
Inside your plan
• Purpose of the evaluation• Questions• What you hope to learn from the question• Analysis technique • How data will be presented
─ Histogram─ Scatterplot─ Time series
What to report• Count (frequencies)• Percentage• Mean• Mode• Median• Range• Standard deviation• Variance• Ranking
Reflect
• Did different experiments show different results?• Randomisation• Larger sample size• Bias
• Were there findings that surprised you?• Where there unexpected patterns?
• Are there things you don’t understand very well – further study needed?
Cheat Sheet