Exam (elaborations) MATH 225N Week 3 Statistics Central Tendancy Questions and Answers

Select the correct answer below: The data are skewed to the left. The data are skewed to the right. The data are symmetric. Which of the following frequency tables show a skewed data set? Select all answers that apply. Select all that apply: Select all that apply: Value Frequency 5 2 6 5 7 9 8 15 9 18 10 24 11 19 12 15 13 10 14 4 Value Frequency 13 2 14 5 15 14 16 13 17 23 18 26 MATH 225N Week 3 Statistics Central Tendancy Questions and Answers 19 15 20 2 Value Frequency 5 1 6 1 7 9 8 20 9 24 10 20 11 9 12 4 13 1 14 1 15 1 Value Frequency 0 4 1 12 2 23 3 28 4 17 5 7 6 6 7 3 Which of the following frequency tables show a skewed data set? Select all answers that apply. Select all that apply:  Value Frequency 0 2 1 11 2 30 3 22 4 15 5 12 6 6 7 1 8 1 Value Frequency 4 1 5 2 6 3 7 7 8 19 9 17 10 17 11 15 12 12 13 4 14 1 15 2 Value Frequency 13 1 14 6 15 9 16 15 17 27 18 28 19 10 20 4 Value Frequency 3 1 4 0 5 1 6 5 7 9 8 12 9 12 10 18 11 12 12 17 13 11 14 0 15 1 16 0 17 1 Which of the following frequency tables shows a skewed data set? Select all answers that apply. Select all that apply: Value Frequency 7 4 8 8 9 12 10 16 11 15 12 13 13 10 14 5 Value Frequency 5 3 6 3 7 8 8 12 9 15 10 19 11 19 12 10 13 4 14 3 15 3 16 1 Value Frequency 12 1 13 2 14 3 15 13 16 10 17 26 18 25 19 15 20 5 Value Frequency 0 9 1 21 2 23 3 18 4 15 5 9 6 3 7 2 For the following dataset, you are interested to determine the "spread" of the data. Would you employ calculations for the sample standard deviation, or population standard deviation for this dataset: Ages of all students in a Statistics course with an enrollment of 30 students. Select the correct answer below: Use calculations for sample standard deviation Use calculations for population standard deviation Which of the following lists of data has the smallest standard deviation? Select the correct answer below: 11, 17, 9, 4, 4, 6, 6, 9, 8, 18 29, 21, 21, 28, 28, 26, 24, 24, 17, 23 6, 8, 10, 6, 8, 8, 10, 7, 10, 10 23, 19, 12, 19, 17, 18, 16, 10, 12, 21 17, 12, 6, 6, 15, 16, 20, 20, 5, 17 Remember that standard deviation is a measure of how spread out the values are. The list 6, 8, 10, 6, 8, 8, 10, 7, 10, 10 has the smallest standard deviation because its values are all relatively close together. Which of the data sets represented by the following histograms has the smallest standard deviation? A company is interested to know the variation in yearly sales amount for all 5 salespeople in the company. The dataset shown below is the sales amount sold by the 5 salespeople in the company (expressed in thousands of dollars): 40,60,65,70,80 Find the variance for this dataset. Provide your answer below: Variance = 176 (population “all’ Variance) The data below are the monthly average high temperatures for November, December, January, and February in New York City from the Country Studies/Area Handbook Series sponsored by the U.S. Department of the Army between 1986 and 1998. What is the sample standard deviation? 54,42,40,40 Round the final answer to one decimal place. Provide your answer below: 6.733 The following data values represent the daily amount spent by a family during a 7 day summer vacation. Find the sample standard deviation of this dataset: $96, $125, $80, $110, $75, $100, $121  Round the final answer to one decimal place. Answer 19.1 Which of the following lists of data has the smallest standard deviation? Select the correct answer below: 30, 21, 19, 17, 16, 32, 26, 25, 19, 16 5, 11, 15, 7, 5, 9, 8, 16, 14, 11 25, 24, 28, 18, 32, 34, 34, 22, 28, 19 17, 19, 17, 18, 17, 16, 16, 16, 17, 20 9, 16, 14, 22, 20, 9, 19, 16, 21, 8 Which of the following lists of data has the smallest standard deviation? Select the correct answer below: 13, 12, 12, 13, 11, 12, 12, 14, 13, 11 25, 26, 23, 17, 21, 28, 28, 23, 25, 16 5, 21, 13, 12, 19, 10, 16, 19, 8, 7 17, 16, 9, 10, 14, 6, 8, 16, 16, 2 33, 33, 30, 32, 31, 24, 28, 23, 24, 23 Find the median of the following set of miles per gallon for randomly selected sports cars. 36,22,24,30,44,13,21,34,18 Provide your answer below: 24 (arrange smallest to largest and find middle) Find the mode of the following number of times each machine in a car factory needed to be fixed within the last year. 2,5,6,12,14,12,6,2,5,3,14,5 Provide your answer below: 5 (# that occurs most often in the set) Laura runs at the park after school and wants to know the mean number of miles she runs. The numbers for the miles run each day so far are listed below. 8,9,7,13,3,9,14 Find the mean number of miles she runs daily. Provide your answer below: 9 (average of all numbers) An art collector bought 20 paintings at an art fair, and wants to know the average price of her new paintings. She adds the prices of all the paintings and divides this number by 20 to find an average price of $350 . Is this price a sample mean or a population mean, and which symbol would be used to denote it? Select the correct answer below: Population Mean μ Sample Mean x¯¯¯ Given the following list of the number of pens randomly selected students purchased in the last semester, find the median. 13,7,8,37,32,19,17,32,12,26 Provide your answer below: 18 (because the list has length 10, which is even, we know the median number will be the average of the middle two numbers, 17 and 19. So the median number of pens randomly selected students purchased in the last semester is 18.) Find the mode of the following amounts of exercise (in hours) randomly selected runners completed during a weekend. 2,14,14,4,2,4,1,14,4,4,8 Provide your answer below: 4 (Note that 4 occurs 4 times, which is the greatest frequency) Find the mode of the following list of points earned on a 16 point quiz given during a finance class. 7,7,3,2,7,16,12,16,12 Provide your answer below: 7 Find the median of the following set of data. 35,43,18,35,29,27,19,19 Give your answer as a number only. For example, if you found the median was 34, you would enter 34. Provide your answer below: 28 Each person in a group shuffles a deck of cards and keeps selecting a card until an ace appears. Find the mode of the following number of cards drawn from a deck until an ace appears. 14,10,7,14,9,9,10,12,9,7,12 Provide your answer below: 9 A grandfather wants to know the average height of all his grandchildren. He finds that the heights of his 9 grandchildren are given in inches by 63,71,60,59,74,60,60,75,58. What is the population mean of the height of his grandchildren in inches? Round your answer to the nearest tenth of an inch and do not include units. Provide your answer below: 64.4 Given the following list of the number of pencils randomly selected students used in a school year, find the median. 10,22,6,7,19,5,27 Provide your answer below: 10 A teacher randomly selects 10 out of her 30 students and finds that the mean height of those 10 students is 5′2". Is this a sample mean or a population mean, and which symbol would be used to denote it? Select the correct answer below: Population Mean μ Sample Mean x¯¯¯ A data set lists the number of strikes scored per team during a bowling league championship. For this data set, the minimum is 2, the first quartile is 3, the median is 5, the third quartile is 7, and the maximum is 14. Construct a box-and-whisker plot that shows the number of strikes sco