MICHAEL DEL VECCHIO



TEST 1 - SOLUTIONTest 1: Chapter 1 and 3Use the Following Table for Questions 1 thru 7Mr. Smith's ClassStudent IDMajorGPAAgeClass1234Math3.219Freshmen2314Biology2.918Freshmen1123Math3.420Sophmore1458English2.621Junior1856Math2.819Sophmore1259Math3.322Senior2963Biology3.320Junior2413Math2.118FreshmenQuantitative?Variables are GPA and AGEThe best label is Student IDThe Mean GPA is 2.95 (Two Decimals)The Median of the Age is 19.5?(One Decimal)The IQR of the GPA is .6 One Decimal No Leading Zero)What is the Sample Standard Deviation of the Age?? 2.41 (ROUND TO TWO DECIMAL PLACES)The Categorical Variables are Major and Class.If the Variance of a data set was 9, then what is the standard deviation? std = 9 = 3A histogram with a long left tail indicates:Has a very negative AverageHas an average larger then its medianHas an average smaller then its medianWas obtained in a manner producing BiasThe z-score separating the top 55% would be: NEGATIVE <0 (0, <0, >0, Need more info) A study on height of males at Coastal University revealed a normal distribution with an average height of 66 inches with a standard deviation of 2.0 inches.? Your friend Matt is 72 inches tall.? We can conclude:Has an average smaller then its medianLess then 2% of the males are likely to be tallerMatt is 3 Standard Deviations above the averageMatt is 3 Standard Deviations below the averageIn 1998?the World Health Organization reported that for Canada the results for Diabolic Blood Pressure had a mean of 78?mmHg and a standard?deviation of 11 mmHg. ?Assuming that Diabolic Blood Pressure measurements are Normally distributed, what is the measurement that represents the 80th percentile of the distribution? Measurement: x = invNorm(.80, 78, 11) = 87.3 (ONE DECIMAL)A Tool and die company have been contracted to produce metal castings into which a hole must be drilled to a diameter of 2.5cm, Because of the variability in the drilling process the actual diameter of the hole is normally distributed with a mean of 2.5 cm and a standard deviation of 0.1cm. What proportion of the holes drilled are within 0.2cm of the desired value?Proportion = ncdf(2.3, 2.7, 2.5, .1) = .9545 Given X~ N(100, 15) Find the P(X > 110) = ncdf(110, 1000, 100, 15) = .252 (THREE DECIMALS)Given X~ N(100, 15) Find the P(90 < X < 110) = ncdf(90, 110, 100, 15) = .495 (THREE DECIMALS)Given Test Scores X~N(100, 15)Find Test Scores the represent Upper 20%Test Score = invNorm(.80, 100, 15) = 112.62 (Two Decimal Places)In a recent study, a random sample of children in grades 2 through 4 showed a significant negative relationship between the amount of homework assigned and the students attitudes. What type of study is this? ______________________________________________(Experiment, Establishing Relationship through Correlation, Observational Study or Block Design with grades as blocks)In a recent study, a random sample of children in grades 2 through 4 showed a significant negative relationship between the amount of homework assigned and the students attitudes.What type of variable is the amount of homework assigned?(Lurking, Confounding, Response, Explanatory) Suppose you want to determine if there are differences in the average prices among items at three local supermarket chains.What type of study would work best?(Observational, Experiment, Neither would work) Suppose you want to determine if there are differences in the average prices among items at three local?supermarkets chains. ?If a block design were used, what would be an appropriate blocking variable for this study? ____________________________(Supermarket, Type of Item, None of above)Suppose you want to determine if there are differences in the average prices among items at three local supermarkets chains. To reduce bias, how should you select items to use in your study?Choose items you know are commonly purchased.Choose only brand names.Randomly select the appropriate number of times from a list of all possible items in the supermarket.D. Choose a few items that you purchase regularly.Using the Following Table and Line from a Table of Random Digits, Select Three Countries.LINE FROM RANDOM DIGITS TABLE 12561 ? ? ? 09412 ? ? ? 03648 ? ? ? ?51536 ? ? ? ?45961 ? ? ? 63942 ??12 56 10 94 12 03 64 85 15 36 45 96 16 39 42Which Statement is Most Accurate?All Population Means and Sample Means are Normally DistributedAll Population Means are Normally Distributed, but Sample Means May or May Not be Normally DistributedPopulation Means May or May not Be Normally Distributed, but Sample Means Tend to Be Normally DistributedNeither Population Nor Sample Means are Normally DistibutedAt a particular Walmart there are 60 male employees and 40 female employees. The best was to select 10 male and 5 female employees at random without bias is byUsing Stratification and then using a Simple Random Sample within each strataLabeling all the employees and then use Random Digit Table to select the first 15 employees.Get a list of all employees and circle 10 males and 5 femalesThere is no way to randomly select 10 Male and 5 females SAT scores are Normally Distributed with a mean of 1400 and a standard deviation of 200. ?Using t the Empirical Rue or 68-95-99.7 Rule approximately what percent score between 1200 and 1600? Percent 68 WITHIN 1 STANDARD DEVIATION (Number Only No Decimals or % Sign) ................
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