PRACTICAL STUFF

•  Give two reasons why it was important that the student counted the number of stomata in several parts of each piece of leaf tissue.

  1. distribution may not be uniform
  2. obtain a reliable mean
• Suggest reasons why conclusions might not be valid.

  • No stats test so don't know if change is significant
  • Small sample number
• Describe how the student could find out whether there was a significant difference in blink rates between the two age groups.

  • use large sample/group sizes
  • apply stats test
• Explain the advantage of giving these data as percentages.

  easier to compare if sample size effectively the same;different numbers of people in each group;