A bag contains 5 blue, 4 green and 3 yellow balls. All the balls are identical except for colour. Three balls are drawn at random without replacement. Find the probability that:
all three balls have the same colour;
two balls have the same colour.
b.The table shows the ranks of the marks scored by 7 candidates in physics and chemistry tests.
Physics
6
5
4
3
2
7
1
Chemistry
7
6
2
4
1
5
3
Calculate the Spearman’s rank correlation coefficient.
Observation
In part (b), candidates were expected to obtain the following table:
