1. in a batch of 10 items, we wish to extract a sample of 3 without replacement. how many
different samples can we extract?
2. let x and y be independent random variables. suppose the respective expected values
are e(x) = 8 and e(y) = 3 and the respective variances are v(x) = 9 and v(y) = 6. let z be
defined as z = 2x - 3y +5. based on these data, the value of e(z) is_ and the value
of v(z) is
3. the ratio of milk water in 55 liters of adulterated milk is 7: 4. how much water must be
added to make the mixture in a ratio of 7: 6?
a) 5 liters
b) 10 liters
c) 15 liters d) none of these