Paper 5) Practical Skills

Question 1

standard error (S.E)

Answer 1

• reliability of the calculated mean
• larger the S.E, less reliable.

Question 2

standard deviation (s)

Answer 2

• spread of data around the mean
• narrow spread = more reliable
  you can then calculate :
• 95% CL
• error bars

Question 3

95% confidence interval

Answer 3

• 95% probability that true mean lies within this range
• to see whether error bars overlap
• to get a measure of how close the calculated mean is likely to be true

Question 3

error bars

Answer 3

• how close the calculated mean is likely to be true to the actual mean
• overlap in error bars = no sig. differences between 2 means