WEEK 4 MATH 225N STATISTICS: WEEK 4 QUIZ WITH ANSWERS PROVIDED & ALREADY GRADED 100%

Question 1 Alice sells boxes of candy at the baseball game and wants to know the mean number of boxes she sells. The numbers for the games so far are listed below. 16,14,14,21,15 Find the mean boxe s sold. Question 2 Given the following list of prices (in thousands of dollars) of randomly selected trucks at a car dealership, find the median. 20,46,19,14,42,26,33 ________________________________________ Question 3 Each person in a group shuffles a deck of cards and keeps selecting a card until a queen appears. Find the mode of the following number of cards drawn from a deck until a queen appears. 3,12,3,11,5,5,3,10,12 Question 4 The dataset below represents bugs found by a software tester in her product during different phases of testing: 88, 84, 81, 94, 91, 98, 98, 200. The measures of central tendency are given below: Mean: 104.25; Median: 92.5; Mode: 98. Identify the outlier and the measure of central tendency that is affected by the outlier. ________________________________________ ________________________________________ The outlier is 98. The mode is affected by the outlier. The outlier is 98. The mean is affected by the outlier. The outlier is 200. The median is affected by the outlier. Question 5 Given the following histogram, decide if the data is skewed or symmetrical. A bar graph has a horizontal axis titled Values labeled from 2 to 18 in increments of 2 and a vertical axis titled Frequency labeled from 0 to 200 in increments of 50. 14 bars are plotted, above the numbers 2 to 16. From left to right, the heights of the bars are as follows: 1. 5. 10. 40, 75, 125, 190, 180, 130, 125, 60, 25,20, 10. All values are approximate. ________________________________________ The data are skewed to the left. The data are skewed to the right. Question 6 The following data set represents the ages of all seven grandchildren in a family. 4, 5, 11, 12, 11, 8, 5 If the variance of the ages is 9.7, what is the standard deviation? • Round the final answer to one decimal place. ________________________________________ Question 7 Which of the data sets represented by the following box and whisker plots has the smallest standard deviation? Four horizontal box-and-whisker plots share a vertical axis with the classes D, C, B, and A and a horizontal axis from 0 to 120 in increments of 20. The box-and-whisker plot above the class label A has the following five-number summary: 44, 69, 77, 82, and 112. The box-and-whisker plot above the class label B has the following five-number summary: 19, 64, 78, 87, and 121. The box-and-whisker plot above the class label C has the following five-number summary: 60, 72, 75, 80, and 92. The box-and-whisker plot above the class label D has the following five-number summary: 2, 63, 77, 92, and 138. All values are approximate. ________________________________________ ________________________________________ Question 8 The box-and-whisker plot shows the number of books read by history students during the last school year. A box and whisker plot with minimum 4, first quartile 6, median 8, third quartile 10, and maximum 15 What is the range of the data? Question 9 A random sample of house sizes in major city has a sample mean of x¯=1204.9 sq ft and sample standard deviation of s=124.6 sq ft. Use the Empirical Rule to determine the approximate percentage of house sizes that lie between 955.7and 1454.1 sq ft. Round your answer to the nearest whole number (percent). ________________________________________ Question 10 Is the statement below true or false? Independent is the property of two events in which the knowledge that one of the events occurred does not affect the chance the other occurs. ________________________________________ Question 11 Brayden tosses a coin 500 times. Of those 500 times, he observes heads a total of 416 times. Calculations show that the probability of this occurring by chance is less than 0.01, assuming the coin is fair. Determine the meaning of the significance level. ________________________________________ ________________________________________ We expect that 416 of every 500 coin tosses will result in heads. There is certainty that the coin is not a fair coin. The results are not statistically significant at the 0.05 level of significance. Question 12 A spinner contains the numbers 1 through 80. What is the probability that the spinner will land on a number that is not a multiple of 11? • Give your answer in fraction form. ________________________________________ Question 13 Of the following pairs of events, which pair has mutually exclusive events? ________________________________________ That is correct! ________________________________________ rolling a sum greater than 7 from two rolls of a standard die and rolling a 4 for the first throw drawing a 2 and drawing a 4 with replacement from a standard deck of cards drawing a red card and then drawing a black card with replacement from a standard deck of cards Question 14 Fill in the following contingency table and find the number of students who both go to the beach AND go to the mountains. Students Go to the mountains do not go to the mountains Total Go to the beach 36 Do not go to the beach 21 Total 48 95 ________________________________________ Question 15 A group of 140 students at an elementary school were asked if they prefer the color orange to the color green. The results are shown in the table below. Given that a randomly selected survey participant is a male, what is the probability that this student prefers the color green? • Enter your answer as a fraction. Male Female Total Orange 12 50 62 Green 2 73 78 Total Question 16 Researchers want to study whether or not a fear of flying is related to a fear of heights. They surveyed a large group of people and asked them whether or not they had a fear of flying and whether or not they had a fear of heights. The data are shown in the contingency table below. What is the relative risk of being afraid of heights for those who are afraid of flying? Round your answer to two decimal places. Afraid of heights Not afraid of heights Total Afraid of flying 76 33 109 Not afraid of flying Total Question 17 Which of the following frequency tables show a skewed data set? Select all answers that apply. That is correct! Value Frequency 5 1 6 2 7 15 0 16 1 Value Frequency 5 1 6 3 7 8 8 10 9 13 10 26 11 14 12 15 1 16 1 Value Frequency 15 20 3 Value Frequenc 0 5 1 16 2 5 9 6 4 7 2 Question 18 A student wants to know his average homework grade for the first half of his math class. There were 7 homeworks in the first half of the class, and his grades out of 100 are given by 100,90,95,89,92,85,95. What is the population mean of his homework grades? Round your answer to the nearest tenth. ________________________________________ Question 19 The following data set represents the ages of all six grandchildren in a family. Find the variance for this data set of ages: 6, 3, 14, 11, 14, 6 • Round the final answer to one decimal place. ________________________________________ Question 20 A poll was conducted during the final game of the basketball season to determine whether fans wanted to see the defending champions win the game or the challenging team win the game. From the poll, 216 of the 374 residents sampled from urban areas want the defending champions to win the game. In more rural areas, 304 of the 466 residents polled want the defending champions to win the game. Assuming location has nothing to do with team preference, the probability that the data gathered was the result of chance is calculated to be 0.03. What is the correct interpretation of this calculation? ________________________________________ That is correct! ________________________________________ More people from rural areas want the defending champions to win the game. Exactly 216 out of every 374 urban residents want the defending champions to win the game. The data is not statistically significant at the 0.05 level of significance in showing that the proportion of people in rural areas who want the defending champions to win the game is different than the proportion of people in urban areas. Question 21 Find the mode of the following amounts (in thousands of dollars) in savings accounts of randomly selected people aged 25-30. 8,6,8,7,2,2,2,4,4,4,4,7 ________________________________________ Question 22 A deck of cards contains red cards numbered 1,2,3,4,5, blue cards numbered 1,2,3,4,5,6,7,8 and green cards numbered 1,2,3,4,5,6,7,8,9,10. If a single card is picked at random, what is the probability that the card is green? • Give your answer as a fraction. • ________________________________________ Question 23 The five-number summary for a set of data is given below. Min Q1 Median Q3 Max What is the interquartile range of the set of data? ________________________________________ Question 24 The five-number summary for a set of data is given below. Min Q1 Median Q3 Max What is the interquartile range of the set of data? Question 25 The following frequency table summarizes a set of data. What is the five-number summary? Value Frequency 3 3 5 2 10 1 13 1 14 3 1 ________________________________________ That is correct! ________________________________________ Min Q1 Median Q3 Max 3 5 9 15 20 Min Q1 Median Q3 Max Min Q1 Median Q3 Max Min Q1 Median Q3 Max 3 6 7 14 20