Review Sheet for Test III, Fall 2016
Colorado State University, Pueblo
Math 156 — Introduction to Statistics

This last midterm is more of a big quiz than a full midterm: it covers much less material, and you therefore will be expected to finish a much larger part of it in the hour testing period.

Definitions

Terms you should know -- be able to state clearly what they mean, recognize them in examples, and create your own examples of them
  1. bivariate data (a dataset coming from individuals for whom you have two RVs of data)
  2. scatterplots, explanatory/independent variable, and response/dependent variable
  3. the direction, shape, and strength of a relationship in a scatterplot
  4. the [linear/Pearson] correlation coefficient $r$, properties
  5. the [least squares] regression line [LSRL]
  6. for a line [particular an LSRL]: slope, $y$-intercept
  7. interpretation of $r^2$
  8. residuals and what a pattern in the graph of the residuals means
  9. interpolation and extrapolation
  10. scatterplot outliers
  11. words to live by: "Correlation does not imply causation"

Things to know how to do

  1. given a bivariate dataset, make a scatterplot (label axes and put some tickmarks with numbers, of course!)
  2. discuss a scatterplot qualitatively
  3. sketch the LSRL on a scatterplot
  4. compute the equation of the LSRL of a bivariate dataset
  5. interpret the slope and $y$-intercept of the LSRL, or use its coefficients to answer questions about a bivariate dataset
  6. discuss the percentage of change in the dependent variable of a bivariate dataset due to change in the independent variable
  7. estimate the value of the response variable of a bivariate system when the value of the explanatory variable is given to you, and know when that is a good thing to do and when it is statistically dubious (i.e., do interpolation and extrapolation and know which is good and which not so good)
  8. identify outliers in scatterplots
  9. discuss the relationship between correlation and causation
  10. use electronic tools to do any of the computations or graphs mentioned above

Format of the test

The total points for the test will be more than 100 — but not by as much as in previous midterms, since this one covers much less material — as before, you can choose which 100 points you want to do out of the available problems. This means you should definitely choose to do first the problems about which you are the most confident, only coming back for the rest after finishing your first pass through the entire test.

Don't forget your calculator or whatever electronic tool[s] you like and notes or books to consult. While you can consult notes, you should always do so simply to make certain you have the right formula or you are checking all of the appropriate conditions — you should know the general shape of all the formulæ, results, and definitions.

Also in recent work students have been using on-line tools to do a lot of their work for them. While this is OK, you must always explain what the tool is doing, what it's inputs, outputs, and methods are, why it got the answer it did, how the answer would change in different situations, and what the answer means.