Midterm summer 2021 PDF

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Summer 2021 NSU midterm faculty JHK SECTION 16...

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Course: BUS172 (Introduction to Statistics), Semester: Fall 2021 Mid I, Time: 1 hour; Marks: 25 Answer ALL the questions. Instructions: Only hand-written answers are accepted. You must write your name and ID in the answer script. Answers must be written consecutively. Take photo of your answers, convert them to pdf in a single file. Submit the single pdf by 12.45 pm (18 November 2021). Q1. (i) Indicate which of the following variables are quantitative and which

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are qualitative: (a) Color of a car (b) Time to commute from home to work (c) Number of errors in a person’s credit report (d) Economic status (ii) Classify the following as cross-section or time-series data. (a) Gross sales of 200 ice cream parlors in July 2012

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(b) Number of armed robberies each year in Dallas from 1998 to 2012 (c) Number of supermarkets in 40 cities on December 31, 2011 (d) Food bill of a family for each month of 2012 Q2. A local gas station collected data from the day’s receipts, recording the gallons of gasoline each customer purchased. The following table lists the frequency distribution of the gallons of gas purchased by all customers on this one day at this gas station. Gallons of Gas 0 to less than 4 4 to less than 8 8 to less than 12

Number of customers 31 78 49

12 to less than 16 16 to less than 20 20 to less than 24

81 117 13

(a) Find the class midpoints and class boundaries. (b) Prepare the relative frequency and percentage distribution columns. Page 1 of 2

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(c) Explain why you cannot determine exactly how many customers purchased 10 gallons or less. Q3. Consider the following exam scores of all students in a class.

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39, 15, 27, 21, 33, 24, 18, 36, 42, 30 4 (a) Obtain Variance and Standard deviation of exam scores. (b) Draw a box-and-whisker plot of exam scores and comment on your 5 plot. (c) Find an interval so that exam scores will fall within two standard 3 deviations of the mean. Using an appropriate rule, mention the percentage of scores that this interval contains.

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