In: Statistics and Probability
Calculate the sample correlation and covariance for (i) Final_exam and assignment_grade; (ii) Final_exam and Tutorial_attend; and (iii) assignment_grade and Tutorial_ attend. Once again using Excel formulae without the use of Data Analysis Tool Pack very important the teacher wants us to use hand by hand using excel in a step by step manner: e.g. calculating the sample mean which would be sum (x) /n...
we can't use excel formula that is (=covariance(A..)
please show steps with snipping tool.
Final_exam | assignment_grade | Tutorial_attend |
100 | 90 | 5 |
100 | 75 | 5 |
90 | 75 | 5 |
85 | 85 | 5 |
85 | 100 | 5 |
80 | 95 | 5 |
70 | 80 | 5 |
60 | 95 | 5 |
60 | 80 | 5 |
55 | 95 | 5 |
55 | 25 | 4 |
50 | 80 | 5 |
45 | 90 | 5 |
40 | 65 | 5 |
40 | 65 | 4 |
35 | 0 | 3 |
30 | 70 | 4 |
30 | 55 | 4 |
25 | 85 | 5 |
25 | 90 | 4 |
15 | 5 | 3 |
15 | 80 | 5 |
15 | 50 | 5 |
15 | 45 | 3 |
5 | 75 | 3 |
5 | 70 | 4 |
100 | 100 | 5 |
95 | 75 | 5 |
90 | 100 | 5 |
85 | 85 | 5 |
80 | 95 | 5 |
70 | 45 | 5 |
70 | 100 | 5 |
65 | 90 | 5 |
60 | 100 | 5 |
55 | 65 | 4 |
55 | 90 | 5 |
55 | 80 | 4 |
50 | 50 | 5 |
45 | 50 | 4 |
45 | 75 | 3 |
40 | 75 | 5 |
40 | 70 | 5 |
35 | 90 | 4 |
30 | 95 | 5 |
30 | 55 | 5 |
25 | 75 | 4 |
25 | 20 | 3 |
25 | 65 | 2 |
15 | 60 | 4 |
15 | 60 | 4 |
15 | 80 | 5 |
10 | 55 | 4 |
10 | 80 | 2 |
0 | 0 | 2 |
a)
Final_exam assignment_grade
sample size , | n = | 55 | ||
here, x̅ = Σx / n= | 46.64 | , | ȳ = Σy/n = | 70.91 |
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 2565 | 3900 | 43402.72727 | 33504.5 | 17993.18 |
mean | 46.64 | 70.91 | SSxx | SSyy | SSxy |
correlation coefficient , r = Sxy/√(Sx.Sy) = 0.4718
covariance=Σ(x-x̅)(y-ȳ) / (n-1) = 17993.1818/54= 333.207
.........................
Final_exam Tutorial_attend
sample size , | n = | 55 | ||
here, x̅ = Σx / n= | 46.64 | , | ȳ = Σy/n = | 4.36 |
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 2565 | 240 | 43402.72727 | 42.7 | 807.27 |
mean | 46.64 | 4.36 | SSxx | SSyy | SSxy |
correlation coefficient , r = Sxy/√(Sx.Sy)
= 0.5928
covariance=Σ(x-x̅)(y-ȳ) / (n-1) =
807.2727/54= 14.9495
................
assignment_grade Tutorial_attend
sample size , | n = | 55 | ||
here, x̅ = Σx / n= | 70.91 | , | ȳ = Σy/n = | 4.36 |
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 3900 | 240 | 33504.54545 | 42.7 | 696.82 |
mean | 70.91 | 4.36 | SSxx | SSyy | SSxy |
correlation coefficient , r = Sxy/√(Sx.Sy)
= 0.5824
covariance=Σ(x-x̅)(y-ȳ) / (n-1) =
696.8182/54= 12.904
....................
THANKS
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