Video: Trend, scatter and outliers [6:42]
In this video, we begin looking at scatterplots and ways of viewing and interpreting them.
(See also the Review Questions following the movie)
[Illustrated transcript (pdf)]
After you’ve watched this video, you should be able to answer these questions:
- How do we use a scatter plot to predict a new outcome at a given value of the predictor variable?
- How can we find a range of values that is likely to contain the new outcome?
- When will the prediction intervals/ranges be wide and when will they be narrow?
- What must we assume when we use existing data to predict a new outcome?
- In what type of region is it particularly dangerous to make predictions?
- How can we check visually whether a trend line or curve is positioned properly?
- What should the trend value corresponding to a particular predictor-variable value (the value 5 was used in the video) be telling us about?
