Stat 371 Homework 5: Confidence Intervals and Sample Size, Assignments of Statistics

Download Stat 371 Homework 5: Confidence Intervals and Sample Size and more Assignments Statistics in PDF only on Docsity! Stat 371 Homework #5 Due Thursday March 2, 2006 This week’s assignment is about construction and interpretation of confidence intervals, conditions for validity and determination of sample size for a desired confidence interval’s length. There are many assigned problems, but most of them are asking for qualitative answers not needing any calculations, and should not take long. 1. Exercises 6.3, 6.4 and 6.7 (p. 184-185). 2. Exercises 6.13 and 6.15 (p. 194) 3. Exercises 6.19 and 6.21 (p. 196). 4. Exercises 6.27 (p.198), 6.33 and 6.34 (p.205). 5. Exercise 6.17 (on p. 195). Use R to get a normal probability plot. Type in the command qqnorm(Difference) if the data (variable Difference) are stored under the name Difference. You may wish to change the point characters. To this end, try qqnorm(Difference,pch=5) or for instance qqnorm(Difference,pch="$"). 6. Exercises 4.21 (on p.141). Additional question: Is the corresponding histogram of the data symmetric or skewed? If skewed, to what side? 7. Exercise 4.18. Readings: • Chapter 4, section 4. • Chapter 6, sections 4 to 7 inclusive. • Chapter 7, sections 1 to 3. Cecile Ane