Corrections and Notes to Exercises July 25, 2006 In Part III of the laboratory exercises (p.15), there were, prior to July 25, the following mistakes: Line 7 (item b): qnorm() should be pnorm() [ qnorm() gives, for a given normal deviate, the cumulative probability.] Line -2: qnorm() should, again, be pnorm() August 2, 2006 (New versions will be posted shortly). Part I, page 6, Exercise 6: The second ant111b should be vince111b Part II, page 10, Exercise 4: Replace "random sample of 200" with "random sample of 500". Exercise 5: apply(mat,2,mean) should be apply(mat,1,mean) Part IV, page 22, Exercise 7: Replace "simulateSampDist(numINsamp = c(4, 9))" with "sampvalues <- simulateSampDist(numINsamp = c(4, 9))" page 21, Exercise 5: Replace "dens <- density(twot(n=999)) with the two statements " d2 <- twot(n=999) dens <- density(d2) " Part V, page 26, Exercise 4(b): For "age of the earth" read "age of the universe". It may help to explain that according to the relevant cosmological model, the velocity of recession of any galaxy relative to any other galaxy has been constant, independent of time. Those parts of the universe that started with the largest velocities of recession from our galaxy have moved furthest, with no change from the velocity just after after time 0. Thus the time from the beginning should be s/v, where s is distance, and v is velocity. The slope of the least squares line provides a combined estimate, taken over all the galaxies for which data is given. August 16 2006 Part VI, page 29, Exercises 1-4 lngth should be length Note that fitted() and residuals() and other such functions are applied to model objects, i.e., for lm models, to the output from lm(....)