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STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) SPRING 2015 STP 226 EXAM #1 Instructor: Student's name (PRINT):_________________________________________ Class time:______________________________________________ Honor Statement: I have neither given nor received information regarding this exam, and I will not do so until all exams have been graded and returned. Signed ___________________________________ DIRECTIONS: This is a closed book examination. You may use a calculator and one standard 8X11 page with hand written notes, no completely solved problems are allowed (one side only). Turn in the notes with your exam. Formulas and tables are provided on the last pages of the exam. There are 21 questions. In questions 1-8 provide complete and well-organized answers with all work showing, calculator may be used unless it is otherwise stated in the question. Questions 9-21 are multiple choice. Place selected answers in the table provided on the back page of the test, before the formula page. Relax and good luck! STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) Question#1 (5 points) A tax auditor has a pile of tax returns, numbered 1 to 192, of which he needs to select 5 for a special audit. Use a fragment of a random numbers table below to make that selection. Start at the very beginning, go right, make sure to consider appropriate number of digits. 2001908831542100901345620461031569002491112307544012987 Selected numbers are: ______ ______ _______ _______ _______ Question#2 (5 points) An exam is given to students in an introductory statistics course, most of the students scored a good passing grade, but relatively few failed badly, so that the grade distribution was left skewed. Out of the two numbers, 70 and 76, one is representing the mean one the median of the test. Which of the two numbers is the mean, which one is the median? ANSWER: MEAN=_______________MEDIAN: ________________________ Use the following table to answer Questions #3 - #5 The following table gives relative frequency distribution of the top colors for vehicles (cars and light trucks) sold globally in 2010. The table values are based on the sample of 20500 vehicles sold globally in 2010. Color Silver Black White Gray Red Blue Beige/Brown Popularity (% sold) 26% 24% 16% 16% 6% 5% 3% Other colors Question #3 (5 points) Find the percent of vehicles that are of βOther colorsβ. ANSWER:___________________________________ Question #4 (5 points) How many red cars were sold? ANSWER:___________________________________ Question #5 (5 points) If one car from that sample is randomly selected, what is the probability that it will be a Red or Blue car. ANSWER:___________________________________ STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) Use following data in questions 6 and 7 The following are IQ test scores for 10 randomly selected fifth-grade students: 145 139 126 122 125 130 96 110 118 118 Question#6 (5 points) Give 5 numbers summary (label what they are) and make a box plot, use a number line below to mark a proper scale. _________ _______ ________ _________ _________ Question#7 (5 points) Compute IQR and use it to identify outliers, if no outliers present, state it. Show clearly all work. Outliers:________________________________________ Question#8 (5 points) Probability measures how likely an event is to occur. Match the following probabilities with each statement of likelihood given, two numbers will be left unmatched. 0 0.01 0.3 0.5 0.7 1 a) This event is impossible. It can never occur. Probability=___________ b) This event is certain. It will occur every time. Probability=___________ c) This event will occur more often than not. Probability=___________ d) This event is very unlikely, but it will occur once in a while in a long sequence of trials. Probability=___________ STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) Questions #9- #21 are multiple choice (5 points each) , select a correct response and mark a letter of that response in the table given on the front page of the test. Use following information for Questions #9 - #10 In 2011 the distribution of Iowa Test vocabulary scores for seventh-grade students in Tempe School District had mean π = 6.84 points and Standard deviation π = 1.55points Question#9 Use Three-Standard-Deviations Rule to fill in the blanks in the following statement: Most of the seventh-grade students in Tempe School District had Iowa Test vocabulary scores between ___________ and _____________points A) 3.84 and 9.84 B) 2.29 and 11.39 C) 2.19 and 11.49 D) none of these Question #10 One of the students that took the test had a z-score z=1.23, what was his test score (round it to 2 decimal places)? A) 8.07 B) 5.61 C) 8.75 D) 9.62 E) none of these Use following information in Questions #11 -#13 In the fuel economy survey of 2011 vehicles the following information was collected (i) Make and Model (ii) Car type (iii) Transmission type (iv) Number of cylinders (v) City mpg (vi) Highway mpg Question#11 List all of the above variables that are qualitative . A) (iv) , (v) and (vi) B) (i), (ii) and (iii) C) only (i) and (iii) D) only (v) and (vi) Question#12 Which type of the graphical display will be appropriate to choice to summarize the City mpg data? A)Pie chart and Bar Chart B) Histogram and Pie chart C)Bar chart and Dot Plot D) Histogram and Stem-and-leaf diagram Question #13 The following are number of cylinders in 12 randomly selected vehicles from that survey 4,4,4,6,6,6,6,8,8,6,6,6 Give mode for the presented data set. A) no mode B) 4 and 6 C) 8 D) 6 STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) Use the following plot to answer Questions #14-#15 The Box Plot below summarizes commuting times to work (in minutes) for a random sample of 60 North Carolina workers. Question #14 Use the above graph to fill in the blanks in the following statement: 25% of the workers in that sample commute to work _________________minutes or less. A) 20 B) 10 C) 30 D) 40 E) none of these Question #15 Use the plot to select the best description for the shape of the data it represents: A) Uniform B) Right Skewed C) Left Skewed D) Bell Shaped Question #16 According to the National Vital Statistics Reports in all of 2013, 1.1% of live births were delivered by forceps and 3.7% were delivered by vacuum extraction. What is the probability that a live baby was delivered without the use of forceps or vacuum extraction? A) 0.048 B) 0.9593 C) 0.952 D) 0.52 E) 0.0407 STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) Use Standard Normal Table to answer questions #17-#18 Question#17 Find area between z1=1.76 and z2=2.15, give 4 decimal places. A) 0.9766 B) 0.0234 C) 0.9216 D) 0.9446 E) 0.0684 Question#18 Find 74th percentile of N(0,1) A) 0.7704 B) 0.2296 C) 0.64 D) 0.65 E) 0.26 Use following information in questions #19 - #20 The distribution of bladder volume in men is approximately Normal with mean π = 550ππ and standard deviation π = 100ππ Question#19 What proportion of male bladders have volumes larger than 500 ml? A) 0.6915 B) 0.3085 C) 0.7881 D) 0.2119 E) 0.5 Question#20 What is the probability that randomly selected male will have a bladder volume smaller than 400 ml? A) 0.9332 B) 0.2912 C) 0.0668 D) 0.5455 E) 1.5 Question#21 (Extra Credit ) Which of the following statements are False? 1) If standard deviation equals 0, all data points must be equal to 0. 2) The standard deviation can be negative. 3) If the mean is large, the standard deviation will be large also. A) All are False. B) None are False C) Only 2 and 3 are False D) Only 3 is False STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) Write letter answers (A-E as appropriate) to questions 9-21 and Extra Credit Question in the table below: Question#9 Question#10 Question#11 Question#12 Question#13 Question#14 Question#15 Question#16 Question#17 Question#18 Question#19 Question#20 Question#21 Extra Credit STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) FORMULAS: π= Sample statistics: β ππ Computational Formul a π , Defining Formula π= ββ ππ πβ (β ππ ) π π=β β(ππ βπ)π πβπ π πβπ , Range=Max-Min , IQR= Q3-Q1 , LL=Q1-1.5(IQR) , UL=Q3+1.5(IQR) Population parameters: π= β π₯π π β(π₯π βπ)2 π=β π or β π₯π2 π=β π β π2 π§= π₯βπ π Probability P(E)=f/N P(notA)=1-P(A), P(A or B) = P(A) + P(B) - P(A and B) Normal Distribution Standard score or z-score π§ = π₯βπ π , If π₯~π(π, π)then π§~π(0,1) STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only) STP226 Spring 2015 Exam #1 Instructor: Student may have one page of hand written notes (one side only)
