Question

The table shows the performance of a selection of 117 stocks after one year. (Take S to be the set of all stocks represented in the table. If a stock stayed within 20% of its original value, it is classified as "unchanged".)

	Companies			Total
	Pharmaceutical P	Electronic E	Internet I
Increased V	13	3	19	35
Unchanged N	37	0	10	47
Decreased D	13	3	19	35
Total	63	6	48	117

Compute

n(P ∪ N').

What does this number represent?

n(P ∪ N') is the number of stocks that were not pharmaceutical stocks and were unchanged after a year.

n(P ∪ N') is the number of stocks that were either pharmaceutical stocks, or were unchanged after a year (or both).    

n(P ∪ N') is the number of stocks that were either pharmaceutical stocks, or were not unchanged after a year (or both).

n(P ∪ N') is the number of stocks that were pharmaceutical stocks and were not unchanged after a year.

n(P ∪ N') is the number of stocks that were either not pharmaceutical stocks, or were not unchanged after a year (or both).

Answer 1

Here we have three companies with values either changes or remain unchanged. Then the value can be obtained by considering its intersection values.