MAT 142 Extra chapter 3 practice part 1

Grima MAT 142 Extra chapter 3 practice part 1 1) A mean average of 90 on 7 exams is needed to get an A for a course. On her first 6 exams, Ellie received grades of 95, 70, 100, 90, 92 and 85. a) What grade must she receive on her last exam to get an A? b) If her lowest grade of the exams already taken is to be dropped, what grade must she receive on her last exam to get an A? 2) A mean average of 70 on 5 exams is needed to get a C for a course. On her first 4 exams, Ellie received grades of 80, 70, 40 and 85. a) What grade must she receive on her last exam to get a C? b) If her lowest grade of the exams already taken is to be dropped, what grade must she receive on her last exam to get a C? 3) Determine the range and standard deviation of the set of data, round to the nearest hundredth when applicable. You may use your calculator to calculate standard deviation. Remember to select the “s”. Round to 2 decimals when needed. 7,9,11,15,17,19,21 4) Use the following data, which show the result of test scores on a recent Organic Chemistry exam 50 55 59 60 70 70 70 76 85 90 91 99 a) Construct a frequency distribution with first class 50-59. b) Compute the total number of observations. c) Compute the width of each class. d) Find the midpoint of the third class. e) Find the modal class (or classes). f) Find the class limits of the next class if an additional class was added). 5) Create a frequency histogram and a frequency polygon from the data in the frequency distribution you created in problem 4. 6) Determine the mean, median, mode and midrange for the data: 1,2,3,3,5,6,8,12 7) The pie chart shows the blood type of 25 people who recently donated blood. a) How many had type B blood? b) How many more donors had type O blood than type B? 8) 79 people were asked how many siblings they have. The results are summarized in the frequency histogram belos. a) How many of the people had 5 or more siblings? b) How many had fewer than 3 siblings? Answers to most of the problems: 1a) 98 1b) 78 2a) 75 2b) 45 3) range 14 Stan Dev 5.27 4) Frequency Distribution Test Score Number of students 50 -59 3 60 - 69 1 70 - 79 4 80 - 89 1 90 - 99 3 Total 12 4b) 12 4c) 10 4d) 74.5 4e) 70 – 79 4f) 100 - 109 5) no room for answer. 6) mean 5, median 4 mode 3 midrange 6.5 7a) 5 7b) 4 8a) 11 8b) 44