Question

The probability that a single radar station will detect an enemy plane is 0.65.

(a) How many such stations are required to be 98% certain that an enemy plane flying over will be detected by at least one station?
stations

(b) If five stations are in use, what is the expected number of stations that will detect an enemy plane? (Round your answer to one decimal place.)
stations

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The Denver Post reported that a recent Audit of Los Angeles 911 calls showed that 85% were not emergencies. Suppose the 911 operators in Los Angeles have just received two calls.

(a) What is the probability that all two calls are, in fact, emergencies? (Round your answer to three decimal places.)


(b) What is the probability that one or more calls are not emergencies? (Round your answer to three decimal places.)


(c) How many calls n would the 911 operators need to answer to be 96% (or more) sure that at least one call is, in fact, an emergency? (Enter your answer as a whole number.)
calls

Answer 1

need 'n' rabor stations Suffore we Ihm PL ena Heam Hlane fyig ores ill be dett deteched an at loalf Mndion one over mill 1-7L emeny ple atected ty auy of the shabions not Le de (0.35) find the smalleut 'nsuch 1- We naed to Hert 1-(0.35)0.2 (o.35 0.02 O02) an L (o.35) 3.73 need 4 tader Nation S07 we col

det x be e number ot ahations in stich a will be detected, auute thure 5 ntims X~Bin (5,0.65) E(x)S5x 0.65 = 3.25 c3.2 be bhe nunmber ot calle out-of two Calle eies Then X~Bin(2, 0.85) Po calls are not Reeeived whri amergenecie are e 2 O.002 0.0225 bPL emergeneies = P[X - 1- PLX=0 Calls are not one s moce 1-0.0225=0.97750.978

e)dut, have to rnecsive 'n' calls Pat leart one call is an eare F1-Pno calls ut of in' calls emergeneies W - 1-(0.85 We need to fiud the mallest 'n', uch hal 1-(0.85)0.96 ?(0.25)0.04 Log e.04) as (0.85)<o 19.81 head to neceive at least 20 calls LEAVE AN UPVOTE! PLEASE