STAT 200 EXAM 2 March 20 2000 FORM B Questions 1 5 An equation is determined which describes relationship between the distance in feet at which an individual can see a highway sign and his or her age The equation is Average Distance 600 3 Age 1 Estimate the distance for an individual who is 20 years old A 597 B 20 C 11 940 D 540 2 How much does the estimated distance change when age is increased by 1 A goes down by 1 B goes down by 3 C goes up by 1 D Goes up by 3 3 Two people differ in age by 10 years What is the estimated difference in the distances at which they can see the sign A 10 B 30 C 570 D Can t be determined from this informtaion 4 Based on the equation what s the direction of the correlation between distance and age A Positive B Negative C Zero D Direction can t be determined 5 Based on the equation what s the strength of the relationship between distance and age A There s a strong relationship B There s a weak relationship C There s no relationship D strength can t be determined from the equation Questions 6 8 refer to the following plots 6 Which plot shows a relationship between for which the correlation is about 0 A Plot A B Plot B C Plot C 7 Which plot shows the strongest linear relationship between the two variables A Plot A B Plot B C Plot C 8 In scrambled order correlations for the three graphs are 0 9 0 0 5 Which graph most appropriately matches with the correlation 0 5 A Plot A B Plot B C Plot C Page 2 9 What will happen to the value of the correlation if the outlier is removed from the following plot A It will increase B B It will decrease C C It will stay the same 10 For which one of these relationships could we use a regression analysis Only one choice is correct A Relationship between weight and height B Relationship between political party membership and opinion about abortion C Relationship between gender and whether person has a tattoo D Relationship between eye color blue brown etc and hair color blond etc 11 The following correlation matrix was generatd using Minitab The variables are height left foot length nose length and weight for a sample of Stat 200 students Correlations Pearson LeftFoot Nose Weight Height LeftFoot 0 319 0 092 0 064 0 484 0 283 Nose 0 126 Which pair of variables has the weakes linear relationship A height and weight B nose length and weight C nose length and left foot length D weight and left foot length 12 A confidence interval will be used to estimate a proportion For the same sample how do the widths of a 95 confidence interval and a 90 confidence interval compare A The 95 confidence interval will be wider B The 90 confidence interval will be wider C The widths of the two intervals will be the same D It s impossible to know how the widths will compare 13 A recent Gallup Poll estimated that 70 of American adults are in favor of capital punishment The margin of error for the poll was 3 Which of the following is a 95 confidence interval for the proportion of American adults who are in favor of capital punishment A 64 to 76 B 69 to 71 C 67 to 73 D Impossible to determine because we don t know the sample size Page 3 14 Which one of the following statements is correct A For 95 of all random samples from a population the 95 confidence interval will contain the sample proportion B For 95 of all random samples from a population the 95 confidence interval will contain the population proportion C For 95 of all random samples from a population the sample proportion will equal the population proportion 15 Which of the following correctly describes the relationship between p and p in a problem in which we re estimating a proportion A p is an estimate of p B p is an estimate of p C p and p are always equal 16 True or False The normal curve is a good approximation to the distribution of any quantitative variable A True B False 17 Suppose that in a clinical trial involving a sample of 200 individuals 160 individuals are successfully treated with a new medication Which of the following is a 95 confidence interval for the proportion successfully treated with the new medication A 0 80 2 B 0 16 2 C 0 80 1 0 80 200 0 16 1 0 16 200 0 16 1 65 D 0 80 3 0 16 1 0 16 20 0 80 1 0 80 200 18 Sleep apnea is a condition of irregular breathing during sleep Suppose that a medical researcher determines based on a random sample that a 95 confidence interval for the proportion of men who have sleep apnea is 0 24 to 0 30 The researcher also determines that a 95 confidence interval for the proportion of women who have sleep apnea is 0 06 to 0 14 Based on these confidence intervals which of the following is an appropriate conclusion A It is safe to say that the proportion with apnea is different for men than for women B The proportion with apnea is about the same for men and women C No conclusion is possible because we don t know the sample sizes Page 4 19 The Gallup Poll reported the results of a survey of 625 adult employed Americans taken to assess job satisfaction The margin of error was reported to be 4 Which choice best describes the 4 margin of error A There s a 4 chance that the survey is wrong B There s a 95 chance that sample and population percentages differ by less than 4 C The difference between the sample and population percentages is exactly 4 D There s a 95 chance that sample and population percentages differ by more than 4 20 Each choice below is a factor affecting the accuracy of a survey Only one of the choices is measured by the margin of error that s usually reported by the newspapers Which factor is measured by the margin of error of a survey A False responses by the participants B Inappropriate sampling frame C Sample size number of people in sample D Badly worded questions 21 The Gallup Poll organization divides the country into four regions of about equal population size and then randomly samples 250 adults from each region What sampling method is this A Volunteer B Systematic C Simple random D Stratified 22 The Daily Collegian conducts a poll of students who live in dorms First they randomly select 6 dormitories Then they survey 20 students in each dorm What sampling method is this A Cluster B Systematic C Simple random D Stratified 23 Imagine that a newspaper picks people for a survey by calling the tenth name …