Answer questions 1-10:

Question 1 (2 points) A major reason to use a stratied random sample rather than a simple random sample would be: . I. It's often easier to do than other types of random sampling. . II. The sample is more likely to be random. . III. It has a good chance of being representative of the p0pulation. O a | only 0 b H only 0 C \"I only 0 d land I\" only 0 e land II only Question 2 (2 points) Consider the following four studies: I. A survey of newspaper editors examines their political views about foreign policy issues. The analysis and conclusion involves a summary of the survey results. ||. Third graders are randomly sampled and assigned to an intensive language course. Their performance on a year-end language test is compared to students who did not take the course. III. A study compares the change in home values between 1990-1999 in ten different neighborhoods in Seattle. The results Show that there's a higher percentage change over time in less afuent neighborhoods. IV. A study compares the durability of machine parts. The comparison looks at machines that were purchased with new metal alloy parts and at those purchased with old metal alloy parts. The results show that durability increases with the use of the new alloy. Which examples are experiments? 0 a land ll only 0 b IlandIVonly O c lonly 0 d H only 0 e m and IV only Question 3 (2 points) For a semester project, a student needs to select a random sample of 10 students from his senior class of 250. He carefully numbers the class list from 000 to 249 and then uses a random number generator to obtain 3-digit random numbers. The 10 unique numbers are his sample. He notices that they all belong to the same honors AP Calculus class. Another student claims that this could not be a random sample. Which of the following is true? 0 a The sample drawn is so unlikely that it could not be considered a random sample. 0 b Since the selected students are not representative the entire senior class, this is not a random sample. 0 c Whether a sample is a random sample or not is determined by the sampling method, not the results. The method used here is OK. 0 d A sample size of10 is too small to be a random sample of 250. 0 e The class should have been numbered from 001 to 250 rather than from 000-249 to produce a better random sample. Question 4 (2 points) A recent survey by a large circulation Canadian magazine on the contribution of universities to the economy was circulated to 394 people who the magazine decided "are most likely to know how important are universities to the Canadian economy". The main problem with using these results to draw conclusions about the general public's perception is: O a selection bias 0 b nonresponse bias 0 c interviewer bias 0 d voluntary response bias Question 5 (2 points) Which of the following is the best representative sample of the adult population in the United States? 0 a Simple random sample of 10,000 adults from different city phone books 0 b Simple random sample of 10,000 voters from across the country 0 c Sample of 50,000 individuals at the Superbowl (which draws from all over the country) 0 d Simple random sample of 1,000 adults from across the country 0 e Sample of 50,000 members of AARP (American Association of Retired Persons) Question 6 (2 points) An important reason a market researcher collects data using a stratified random sample rather than a simple random sample is: to collect data at a lower cost. to eliminate, or a least reduce, bias. to make a representative sample more likely than one produced by simple random sampling. convenient data collection. 00000 to have a systematic way of obtaining the data. Question 7 (2 points) You're interested in whether tutoring is more effective when the student volunteers to be tutored. You compare the test scores of two groups of students: those who chose to go to after-school tutoring sessions and those who are required to go to the sessions by the school administration. This is an example of a (an): O a experiment. Ob observational study. O c anecdotal study. O d survey analysis.Question 8 (2 points) Many statisticians say that the U.S. Census, which attempts to count every population member directly, is significantly less accurate than a count estimated by random sampling. Why might a count estimated from random samples be more accurate than a census? (Choose the best answer.) a Random samples are scientific whereas censuses are not. Ob A true census takes so long that by the time all population members are counted, the population has changed. C A census often can't find every population member, so some groups (such as the homeless) are often under-represented. d A census is a haphazard sample, and census takers may be bribed by households. O e A census is an old method written into law before anyone knew anything about statistics.Question 9 (2 points) A plant researcher identifies a sample of plots of land to examine the effect of a new fertilizer on the speed of growth of a particular crop. She treats half the plots of crops with the new fertilizer (MiracleGro), and the other half with the more traditional brand (SuperFert). She observes that crop growth in both sets of plots is almost identical. The data collection strategy she has used is a (an): O a anecdotal study. b observational study. C survey analysis. O d quasi-study. O e experiment.Question 10 (2 points) Consider the following four rows from a random number table: 55588994047070841098 46563569344839451719 12975132581304845144 72321819400036002428 Use the random number table above to draw a sample size of 10. Twenty percent of the population has a trait you wish find. A success is defined as a 0 or 1. Draw eight samples of size 10 by reading each row from left to right. What are the greatest and fewest number of successes you might expect in a sample of size 10? O a 4, 1 Ob 3, 0 C 4, 0 Od 3, 1 O e 4, 2