presenting data

• when are bar charts used?

  when data falls into categories
• how are the axis labelled on a bar chart?

  x= categories

  y= frequencies
• rules when drawing a bar chart?

  equal width columns, no touching, can’t be converted into a line graph, can’t be used to show/compare distributions
• when are histograms used?

  when results can be put into a continuous orer
• how are the axis labelled on a histogram?

  x=all possible scores in order

  y=number of participants
• rules to drawing a histogram?

  no spaces between columns, can be converted into a line graph
• what are line graphs useful for?

  comparing two distributions on the same graph
• what is a frequency distribution?

  a summary of how often different scores occur within a sample of scores
• what is frequency?

  how often something happens
• what is a skewed distribution?

  when scores aren’t distributed equally around the mean
• what is a positively skewed distribution?

  right skewed

  when the mean is to the right of the mode and median

  (right foot on the page, mean person is far away so it is positive)
• what is a negatively skewed distribution?

  left skewed

  mean is to the left of the mode and median

  (mean person is closer so it is negative)

  (left handed=witches killed= negative)
• what is a normal distribution?

  a classic bell-shaped curve where scores are equally distributed around the mean. the mean, median and mode