Frequency Distribution

Frequency Distribution

A Frequency Distribution is simply a summary of how often each score occurs by grouping scores together.

Cannot Find This OVERHEAD: LIST OF ALL POSSIBLE SCORES/NUMBER OF OCCURRENCES

Graphs: must be clearly titled

all symbols clearly identified
Histogram
vertical bar graph

columns touch each other
Histogram: vertical bar graph

columns touch each other

Frequency distributions come in three types:

symmetrical, positively or negatively skewed

Cannot Find This OVERHEAD: THREE DISTRIBUTIONS

If a distribution is symmetrical, the lower half of the distribution mirrors the upper half
- in symmetrical distributions, mean, median and mode will be the same (unless it is bimodal)
In skewed distributions, median comes between mean and mode
- because mean will be dragged down or up by the few scores out on the extreme tail, while mode will hang out where the greatest action is
If the scores are piled up at the low end, and "tail off" near the high end, it's positively skewed
If the scores are piled up at the high end, and "tail off" near the low end, then it's negatively skewed
Positive or Negative by the way the tail points --if tail points to high end, it's positive; if tail points towards negative end, it's negative

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