descriptive statistics

Cards (12)

  • primary data is original data collected first hand
  • secondary data is data that has already been collected and stored by someone else.
  • primary data is more valid as it is specific to the purpose of the study
  • primary data is more time consuming to collect, meaning we could end up with less data
  • measures of central tendency is the typical average score from the data set (mode, median, mean)
  • measures of dispersion is how spread out the scores in a data set are (range, standard deviation)
  • the mean includes all scores but is affected by extreme scores
  • the median and mode don’t include all scores but aren’t affected by extreme scores
  • normal distributions- when the mean, median and mode are at the highest peak of the distribution
  • positive skewed distribution- when the data is concentrated to the left, with the mode and median being below the mean
  • to make a more normal distribution:
    1. adjust difficulty of test
    2. make it easier/ more difficult
    3. so more get a higher/ lower mark
    4. making a more normal distribution
  • negatively skewed data is concentrated to the right with the mode and median being higher than the mean