The number of beetles in a lawn varies with an average of 13
The number of beetles in a lawn varies with an average of 1.3 per square yard. What is the approximate probability of obtaining a sample of 10 yd.² of one with more than 10 Beatles?
The number of beetles in a lawn varies with an average of 1.3 per square yard. What is the approximate probability of obtaining a sample of 10 yd.² of one with more than 10 Beatles?
The number of beetles in a lawn varies with an average of 1.3 per square yard. What is the approximate probability of obtaining a sample of 10 yd.² of one with more than 10 Beatles?
Solution
As in 1 yd^2 there are 1.3 beetles, then, at 10 yd^2, there are 1.3*10 = 13 beetles on the average.
Note that P(more than x) = 1 - P(at most x).
Using a cumulative poisson distribution table or technology, matching
u = the mean number of successes = 13
x = our critical value of successes = 10
Then the cumulative probability of P(at most x) from a table/technology is
P(at most 10 ) = 0.251682027
Thus, the probability of at least 11 successes is
P(more than 10 ) = 0.748317973 [answer]
