A surgical technique is performed on 7 patients. There is a 70% chance of success. Find the probability that the surgery is successful for at least 5 patients and what is the expected number of successes out of 20 surgeries.
My attempt was: P(xmore than or equal to 5)= P(x=5)+ P(x=6) + P(x=7)
and expected number of success for 20 surgeries= P(k success in n trials)= P (k successes in n trials) =(n¦k) p^k q^(n-k), where:
n = the number of trials = 20
k = the number of successes = 0.7
n – k = number of failures = 0.3
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