Past experience has shown that, on the average, only one in ten wells drilled hits oil.
Let X be the random variable that represents the number of drillings until the first
success (oil is struck). Assume that the drillings represent independent events.
(a) List the elements of the sample space for 5 drillings or less. Use W for “success”
and F for “failure” in finding an oil well. Is this a discrete sample space?
Explain.
(b)Assign a value to each sample point and find the probability mass function for
5 drillings or less.
(c) Express the probability function as a formula for x = 1,2,3 ... ∞.
(d)Find P(X = 10) using the formula.
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