Outside the middle school program / Statistics 3 exercises corrected

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1. Extra: about the mean E.903 An examination consists of the following two tests : an oral test (coefficient 4) ; a written test (coefficient 6) . Each test is graded from 0 to 20 . To pass the exam, a candi-date must obtain a minimum average of 10 . The calculation of the average m is given by the following formula : m = 4 x + 6 y 10 where x is the oral mark and y is the written mark. 1 Caroline who got 13 at the oral and 7 at the written will she pass the exam? Justify. 2 Etienne got 7 at the oral. a What grade must Etienne have on the written paper to obtain exactly 10 average? Justify. b Etienne’s parents have promised him a computer if he achieves an average in his exam of 13 or above. What is the minimum mark he must achieve in the written exam to receive this gift? Justify. E.2362 1 A student with only marks out of 20 has an average of 10.4 . Knowing that the sum of his grades is 52, find the num-ber of grades obtained this quarter. 2 In another class, again with marks out of 20, a pupil has an average of 12 this term with five marks. What mark does he need on the sixth and final quiz of the term to achieve an average of 13? 2. Mean of means E.2061 Here are the marks obtained by a stu-dent in mathematics during his year in the fourth grade : First Quarter Second Quarter Third Quarter 12 - 15 - 10 - 14 7 - 1 - 13 13 - 5 - 10 All results will be rounded to the nearest hundredth. 1 Calculate the average of his grades over the whole year. 2 a Calculate this student’s average for each quarter. b Calculate the average of the quarterly averages. https://chingmath.fr chapExoCorrec/903 sacados/903 chapExoCorrec/2362 sacados/2362 chapExoCorrec/2061 sacados/2061