Microsoft word - apstat_chap5_quizreview.doc

Chapter 5 Quiz Review November 19, 2008
Answer questions on another sheet of paper. 1. Canada requires that cars be equipped with “daytime running lights,” headlights that automatically come on at a low level when the car is started. Many manufacturers are now equipping cars sold in the United States with running lights. Will running lights reduce accidents by making cars more visible? (a) Describe the design of an experiment to help answer this question. In particularly what response (b) What cautions do you see that might apply to an experiment on the effects of running lights? 2. Does ginkgo improve memory? The law allows marketers of herbs and other natural substances to make health claims that are not supported by evidence. Brands of ginkgo extract claim to “improve memory and concentration.” A randomized comparative experiment found no evidence for such effects. The subjects were 230 healthy people over 60 years old. They were randomly assigned to ginkgo or a placebo pill (a dummy pill that looks and tastes the same). All the subjects took a battery of tests for learning and memory before treatment started and again after six weeks. (a) What are the explanatory and response variables in this experiment? (b) Outline the design of this experiment. (c) The study was double-blind. What does this mean? 3. Does caffeine affect your ability to pay attention? You are interested in answering this question, and you think that the age of respondents might be a factor in the answer. You have a group of 25 high school and college student volunteers, and another group of 25 working volunteers between the ages of 35 and 45. (a) Design an experiment to study the effects of caffeine on attention. Be careful to specify the procedures and variables you will use, and how you will conduct measurements. (b) Describe how the volunteers will be assigned to groups for the experiment. 4. An engineer is trying to determine the effect of alloy and diameter on the strength of an axel. There are 5 potential alloy mixes and 4 axel diameters. How many different experimental groups will there be? Explain your reasoning. 5. You have been asked to select 20 participants for a drug trial that compares two different treatments for migraine headaches. The researchers have requested a block design (male/female) with control groups for each block. You have been given a list of people willing to participate in the trial, numbered from 01 to 87. The first 42 people are female; the rest are male.
(a) Sketch a diagram for the design of this experiment.
(b) In paragraph form, clearly explain how you will select the subjects for each block.
(c) Beginning at line 123 of the random digits table (below), select the 10 women. Then begin at line 125
to select the 10 men.
58580 81507 27102 56027 55892 33060 41842 81868 71035 09001 43367 49497 72719 96758 27611 91596 96746 12149 37823 71868 18442 35119 62103 39244 96927 19931 36809 74192 77567 88741 48409 41903 6. Assume that you have done a least squares regression computation for the population of zebra mussels in a stream feeding into Lake Erie. The least-squares regression line equation (y = population, x = years since the mussels first reached the stream) is log(y) = 1.206 + .345x (a) According to the equations, how many mussels will be in the stream after 5 years? After 10 years? (b) What percentage growth rate per year does the equation predict?

Source: http://coffman.dublin.k12.oh.us/teachers/teacherpages/king/Statistics/OldMaterials/Chapter_5_6/APStat_Chap5_QuizReview.pdf