Video Transcript
The probability of a cow
contracting an illness at a farm is 0.17. If there are 1,800 cows at the
farm, what is the expected number of infected cows?
In this question, we’ve been asked
to calculate an expected value. To do this, we can recall the
formula for calculating expected values. This tells us that the expected
value equals the probability of an event occurring multiplied by the number of
experiments or trials.
We can now apply this formula to
our question as follows. The expected number of infected
cows equals the probability of a cow contracting an illness multiplied by the total
number of cows. And from the question, we can see
that the probability of a cow contracting an illness at the farm is 0.17 and the
total number of cows at the farm is 1,800. And if we multiply these values
together, we get 306.
Therefore, we have worked out that
the expected number of infected cows at the farm is 306.
