STAT302 Secs 102 103 Summer I 1998 Exam 1 Form A Instructor Julie Hagen Carroll 1 Don t even open this until you are told to do so 2 Be sure to mark your section number 102 or 103 and your test form A B C or D on the scantron 3 Sign your name where indicated on your scantron and write your Wednesday section number and computer number beside it Also you must place your scantron in the correct section stack for next Tuesday 4 There are 20 multiple choice questions on this exam each worth 5 points There is partial credit Please mark your answers clearly on the scantron Multiple marks will be counted wrong 5 You will have 60 minutes to finish this exam 6 If you are caught cheating or helping someone to cheat on this exam you both will receive a grade of zero on the exam You must work alone 7 This exam is worth 100 points and will constitute 25 of your final grade 8 Good luck 1 STAT302 102 103 Exam 1 Form A Summer I 1998 4 Which of the following is a continuous numeric variable A B C D E 1 What is the approximate correlation coefficient r of the data in the scatterplot above A B C D E age in years your exam score out of 100 points your classification your height exactly two of the above 1 5 10 25 Percentiles 1 662996 1 637709 1 604434 1 500942 50 1 051385 75 90 95 99 7622945 0638196 6425944 1 5275 Smallest 1 662996 1 637709 1 604434 1 569302 Largest 140413 0638196 6425944 1 5275 5 How many outliers are there is the data represented above strongly negative moderately negative weak moderately positive strongly positive A B C D E 2 If the point 2 1 is added to the data above which of the following will be affected 0 1 2 3 7 6 What is the shape of the data above A B C D E the correlation coefficient the intercept the slope All of the above will be affected Exactly two of the above will be affected A B C D E 3 Suppose you get a z score 1 2 on this exam Question 10 is really hard so I decide to give everyone credit i e I give 5 points to everyone who missed it What SHOULD you think about this if you got the problem right originally skewed right positively skewed left negatively impossible to tell without a graph uniform normal 7 If you are given a set of 25 observations and you increase the maximum ONLY by 15 which of the following will be true A the mean and the standard deviation will increase B the median and the IQR will increase C the IQR but not the median will increase D Two of the above will be true E None of the above will be true A It doesn t matter since your z score would stay the same B You get gypped since your z score would decrease C You benefit since your z score would increase D Your z score would increase but so would everyone else s E Your z score would decrease but so would everyone else s 8 Which of the following is are true A A correlation coefficient 0 means the least squares line is horizontal flat B A correlation coefficient 0 means that the points don t deviate from the least squares line C A slope 1 means the correlation coefficient 1 D All of the above are true E None of the above are true 2 STAT302 102 103 Exam 1 Form A 9 Which of the Rules for distributions apply to the data above 12 Explain the boxplot for Truck A B C D E A Just because this is a normal quantile plot doesn t mean the data is normal so you can only apply Chebyshev s Rule B The data is approximately normal so you can only apply the Empirical Rule C Both Rules apply to this data D Neither Rule applies to this data E The mean and the median must be equal for the Empirical Rule to apply There are only 5 observations x x Q3 Q1 Q3 x Q1 Q3 x or x Q1 13 Suppose x 5 and sx 2 What is y and sy if y 3x 4 A B C D E 10 Suppose your data is approximately normally distributed with a mean x 25 and standard deviation sx 3 What is the approximate 95th percentile of your data Note the 95th percentile has 95 of the data is below it A B C D E Summer I 1998 y y y y y 15 15 11 11 11 and and and and and sy sy sy sy sy 6 2 10 2 6 14 For a certain dataset you are told that the standard deviation s 0 What else can you say about the dataset 19 22 28 31 34 A B C D E 11 Which of the following indicate that the data is skewed left negatively A The mode tallest bin of the histogram is on the right and the other bins get continually shorter as you go left B The boxplot has the median x closer to Q3 and the maximum than to Q1 and the minimum C The mean x is greater than the median x D All of the above indicate left skewness E Exactly two of the above excluding D 3 the mean x 0 the median x 0 the IQR 0 all of the above none of the above STAT302 102 103 Exam 1 Form A 15 What are the approximate mean and median for the data in the histogram above A The mean is about 1 and the median is less than 1 B The mean is less than 1 and the median is about 1 C The mean is greater than 1 and the median is about 1 D The mean is about 1 and the median is greater than 1 E It can t be determined from a histogram Percentiles 1 889607 1 866672 1 405686 7113619 50 1811576 75 90 95 99 1 124482 1 596731 1 613076 1 914647 A B C D E 4 4 2 3 11 3 13 4 2 3 Smallest 1 889607 1 866672 1 405686 1 19719 Largest 1 545016 1 596731 1 613076 1 914647 1 2 3 5 6 19 Which of the boxplots have the mean and the median approximately equal A 1 and 2 only since they re approximately normal B 1 only C 1 2 and 3 D 3 only E 1 and 3 only 17 Suppose you don t know anything about the shape distribution of your dataset What percentage of the observations can you say are within 1 standard deviation of the mean A B C D E 1 5 10 25 18 Numbering the boxplots from 1 to 6 starting at the left which one corresponds to the output above 16 Given a least …