BRM 2023

BRM Statistics - CORRECT ANSWER-the science of learning from data Individuals - CORRECT ANSWER-objects described by a set of data A variable - CORRECT ANSWER-Any characteristic of an individual. A variable can take different values for different individuals. observational study - CORRECT ANSWER-observes individuals and measures variables of interest but does not attempt to influence the responses response - CORRECT ANSWER-A variable that measures an outcome or result of a study. Population - CORRECT ANSWER-The population in a statistical study is the entire group of individuals about which we want information. Sample - CORRECT ANSWER-A sample is the part of the population from which we actually collect information. We use information from a sample to draw conclusions about the entire population. Census - CORRECT ANSWER-A sample survey that attempts to include the entire population in the sample. Experiment - CORRECT ANSWER-An experiment deliberately imposes some treatment on individuals to measure their responses. The purpose is to study whether the treatment causes a change in the response. A(n) _____________ is the entire collection of subjects about which we would like information. A) individual B) population C) sample D) census - CORRECT ANSWER-A) Population A Pew Research Council Poll recently showed that 23 percent of Americans are religiously unaffiliated. The poll contacted 35,071 adults by telephone. The margin of sampling error was plus or minus 0.6 (six-tenths) of a percentage point. Assume a 95 percent confidence level and no bias. The population for this sample survey is: A) the 23 percent who said that they were religiously unaffiliated. B) all households in the United States. C) all adult residents of the United States. D) the 35,071 people who answered the question. - CORRECT ANSWER-C) all adult residents of the United States. A(n) _____________ is a subset of subjects from the population. A) census B) individual C) sample D) population - CORRECT ANSWER-C) sample The General Social Survey (GSS), conducted by the National Opinion Research Center at the University of Chicago, is a major source of data on social attitudes in the United States. Once each year, 1500 adults are interviewed in their homes all across the country. The subjects are asked their opinions about sex and marriage, attitudes toward women, welfare, foreign policy, and many other issues. The questions on the GSS are considered A) populations. B) individuals. C) samples. D) variables. - CORRECT ANSWER-D) variables In a(n) _____________, all subjects of the population are studied. A) experiment B) sample survey C) census D) observational study - CORRECT ANSWER-C) census The General Social Survey (GSS), conducted by the National Opinion Research Center at the University of Chicago, is a major source of data on social attitudes in the United States. Once each year, 1500 adults are interviewed in their homes all across the country. The subjects are asked their opinions about sex and marriage, attitudes toward women, welfare, foreign policy, and many other issues. The GSS is an example of A) a sample survey. B) anecdotal information. C) an experiment. D) using available data. - CORRECT ANSWER-A) a sample survey biased sample - CORRECT ANSWER-The design of a sample is biased if it systematically favors certain outcomes. Wrong in the same direction. convenience sampling - CORRECT ANSWER-choosing individuals who are easiest to reach voluntary response sample - CORRECT ANSWER-A voluntary response sample chooses itself by responding to a general appeal. Write-in or call-in opinion polls are examples of voluntary response samples. examples of biased samples - CORRECT ANSWER-convenience sampling and voluntary response sample Simple Random Sample (SRS) - CORRECT ANSWER-of size n consists of n individuals from the population chosen in such a way that every set of n individuals has an equal chance to be the sample actually selected. It also gives every possible sample an equal chance to be chosen. table of random digits - CORRECT ANSWER-A long string of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 with these properties: • Each entry in the table is equally likely to be any of the 10 digits 0 through 9. • The entries are independent of each other. That is, knowledge of one part of the table gives no information about any other part. Undercoverage bias - CORRECT ANSWER-Undercoverage occurs when some groups in the population are left out of the process of choosing the sample. Nonresponse bias - CORRECT ANSWER-Nonresponse occurs when an individual chosen for the sample can't be contacted or refuses to participate. Response bias - CORRECT ANSWER-A systematic pattern of incorrect responses in a sample survey leads to response bias. errors in sample surveys - CORRECT ANSWER-Undercoverage Nonresponse Response bias The wording of questions A teacher writes the names of her 30 students on small pieces of paper and places them into a box. She then draws out five names to select students to participate in a survey. These five students are A) a simple random sample of the class. B) a census. C) a voluntary response sample. D) the population. - CORRECT ANSWER-A) a simple random sample of the class. Bias in a sampling method is A) any systematic error that tends to occur in the same direction every time you use this sampling method. B) any error due to practical difficulties such as contacting the subjects selected. C) any error in the sample result, that is, any deviation of the sample result from the truth about the population. D) racism or sexism on the part of those who take the sample. E) the random error due to using chance to select a sample. - CORRECT ANSWER-A) any systematic error that tends to occur in the same direction every time you use this sampling method.