- #1
ver_mathstats
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Homework Statement
Consider the below vector x, which you can copy and paste directly into Matlab. The vector contains the final grades for each student in a large linear algebra course.
x = [59 70 83 89 72 70 54 55 68 61 61 58 75 54 65 55 62 39 43 53 67 100 60 100 61 100 77 60 69 91 82 71 72 70 71 75 72 60 85 83 62 70 80 73 54 34 76 62 63 72 65 53 69 86 59 50 56 69 66 60 59 38 84 87 62 45 97 43 65 51 79 89 64 65 54 79 32 78 62 68 79 70 66 74 73 62 45 93 68 90 76 79 76 82 44 90 76 74 65 71 56 90 68 70 62 75 88 75 96 58 84 88 59 57 75 61 75 72 69 70 69 70 81 65 70 73 97 84 59 67 87 51 67 69 59 82 55 84 73 100 91 82 58 62 75 76 55 63 71 76 66 61 57 85 72 69 82 77 58 64 86 79 57 71 66 62 67 53 35 70 78 97 54 53 56 70 83 70 60 75 82 60 78 64 71 59 72 84 82 94 64 73 57 74 74 67 94 55 77 59 58 59 68 94 80 61 86 76 59 50 65 72 61 61 78 81 91 76 58 78 63 55 54 79 86 61 61 66 63 22 45 58 63 83 61 70 87 88 78 78 72 85 67 92 83 84 73 69 44 59 69 69 84 50 61 82 60 79 56 65 76 88 93 59 65 77 70 83 71 57 99 82 81 65 68 70 76 100 68 65 83 59 40 64 77 73 64 61 57 76 50 91 69 59 72 69 88 54 73 62 58 74 71 72 69 66 69 67 61 85 78 73 85 62 83 63 62 81 72 54 100 68 67 56 83 80 60 64 63 71 70 87 38 73 61 81 75 84 75 70 75 71 77 77 64 75 65 63 54 71 60 68 65 58 56 66 61 83 95 53 66 85 58 65 72 87 68 62 72 79 78 80 75 97 63 74 77 89 59 74 59 58 66 64 68 71 66 49 58 73 62 72 63 57 58 53 68 64 69 89 59 70 70 83 53 71 28 70 49 87 67 69 87 50 61 78 67 71 58 85 54 90 95 52 63 56 64 46 71 58 62 73 89 75 54 75 77 74 65 79 67 77 91 70 70 62 90 65 67 68 53 86 71 52 74 75 77 70 90 79 63 76 42 86 89 79 100 80 85 78 82 55 77 42 60 67 62 83 80 61 81 65 62 92 63 77 66 57 69 65 67 62 85 56 79 70 77 76 67 52 50 70 70 67 61 61 85 67 77 67 53 75 54 61 94 100 53 67 60 59 73 68 51 58 65 80 69 76 53 75 76 58 46 75 63 56 79 64 56 87 63 58 76 72 84 73 68 64 75 55 81 59 69 60 52 53 62 84 71 55 91 85 42 94 76 59 73 78 61 46 77 69 82 63 76 77 67 38 65 67 84 71 69 77 61 71 53 68 86 77 72 77 71 64 94 49 58 59 47 85 55 68 66 76 78 68 61 83 84 46 81 38 36 56 50 78 97 83 84 79 48 98 96 51 41 66 45 80 60 76 84 65 98 74 54 58 60 42 60 71 55 71 84 81 72 82 69 68 70 85 61 94 70 62 87 56 53 70 65 60 65 68 99 89 57 82 67 100 68 69 57 47 63 33 73 54 69 67 78 78 63 68 53 48 41 68 89 73 58 64 63 60 68 79 78 62 64 62 70 67 50 89 62 48 91 74 71 82 76 69 59 81 70 73 60 84 60 74 62 57 74 63 43 51 81 80 62 67 69 64 48 81 42 74 49 77 73 82 74 68 61 57 94 69 54 64 57 63 64 85 82 71 80 66 72 67 61 67 77 86 56 61 68 71 55 59 85 62 64 61 71 89 52 54 65 72 73 76 42 81 91 79 72 65 74 69 66 77 77 78 73 67 65 76 69 64 68 61 82 52 84 44 77 75 86 63 57 56 76 72 87 72 77 55 88 75 83 69 57 96 55 78 76 61 71 56 73 95 74 46 56 74 54 88 61 86 61 51 64 66 85 83 75 30 82 66 60 68 67 78 75 69 55 96 70 70 51 75 74 71 73 76 88 81 57 69 42 74 52 71 98 82 75 79 54 71 55 77 80 69 97 46 49 56 64 51 83 77 47 66 57 73 81 59 78 88 72 58 51 57 76 82 38 53 79 55 78 61 65 40 81 85 81 55 64 83 64 88 64 87 69 67 65 67 46 65 57 47 46 61 57 66 64 69 94 82 50 64 59 79 71 83 87 69 85 65 81 100 61 63 67 56 84 50 61 94 89 73 76 78 62 85 70 47 77 83 52 59 84 80 77 83 38 83 59 87 48 58 77 71 59 48 79 52 83 50 100 57 72 45 84 65 84 72 83 53 66 82 60 82 71 79 71 82 77 56 66]'
(a) What proportion of students failed the course (i.e., got a mark of less than 50)?
(Note that since the answer is a proportion, it must be between 0 and 1.)
(b) What proportion of students got a B-, B, or B+ (i.e., got a mark between 70 and 79, inclusive)?
2. Homework Equations
The Attempt at a Solution
For question (a) I did failCount=sum(x<50) and I got 61 and the proportion I got was 0.0606. Is this correct?
For question (b) I did between= x(x>=70 & x<=79) to obtain all of the grades from 70 to 79 but now I am unsure of how to get the proportion, I did gradeRatio= between/numel(x) however it gave me several different decimal points, I am unsure of where I went wrong?
Thank you.