Spearman correlation - admission "During the admission procedure, the evaluation was performed by commissions and by a special program. " "Based on the ranking of the ten students, decide whether both assessments are dependent." Student A B C D E F G H I J commission grade 4 6 1 5 10 2 7 3 9 8 program grade 1 3 5 7 8 4 6 2 10 9 difference difference squared H0….correlation between the two grading =0 H1….correlation between the two grading <>0 ##### Sheet/List 2 ##### Test1 Test2 You are given test results (points) from two subjects of 8 randomly selected students. 80 65 Determine the correlation of a linear dependence of these results by the Spearman and Pearson coefficients. 50 60 36 35 58 39 72 48 60 44 56 48 68 61 ##### Sheet/List 3 ##### Data displays the association between the IQ of 10 adolescent in a sample with the number of hours they listen to rock music per month. Determine the strength of the correlation between IQ and rock music using both the Pearson’s correlation coefficient and Spearman’s rank correlation. Compare the results. IQ Rock m. rank IQ rank rock d 99 2 120 0 98 25 102 45 123 14 105 20 85 15 110 19 117 22 90 4 ##### Sheet/List 4 ##### Example: Ice Cream Sales The local ice cream shop keeps track of how much ice cream they sell versus the temperature of that day for the last 12 days: Formulate a null hypothesis and verify it by Pearsons and Spearman coefficients H0= There is no correlation between the amount of icecream sold and the temperature outside. H0= There is a correlation. Temperature (°C) Ice Cream Sales ($) rank t rank sales d 14.2 215 11 11 0 16.4 325 9 10 -1 11.9 185 12 12 0 15.2 332 10 9 1 18.5 406 6 8 -2 22.1 522 4 3 1 19.4 412 5 6 -1 25.1 614 1 1 0 23.4 544 2 2 0 18.1 421 7 5 2 22.6 445 3 4 -1 17.2 408 8 7 1 14 sum squared 0.951048951 .=rs "crit(0,05)=" 0.587 The calculated value is larger than critical value. "The null hypothesis is rejected. Therefore, there is a colleration." average 18.7 402.4 differences dx*dy -4.5 -187.4 838.69 -2.3 -77.4 176.12 -6.8 -217.4 1473.00 -3.5 -70.4 244.70 -0.2 3.6 -0.63 3.4 119.6 409.57 0.7 9.6 6.95 6.4 211.6 1359.42 4.7 141.6 668.98 -0.6 18.6 -10.69 3.9 42.6 167.14 -1.5 5.6 -8.24 177.0 174754.9 5325.03 r= 0.957506623 d.o.f.= 10 alpha= 0.05 critical= 0.576 The calculated value is above the critical one. "Therefore, the null hypothesis is rejected. There is a correlation."