Answer:
Step-by-step explanation:
Hello!
The study variable is:
X: number of passengers that rest or sleep during a flight.
The sample taken is n=9 passengers and the probability of success, that is finding a passenger that either rested or sept during the flight, is p=0.80.
I'll use the binomial tables to calculate each probability, these tables give the values of accumulated probability: P(X≤x)
a. P(6)= P(X=6)
To reach the value of selecting exactly 6 passengers you have to look for the probability accumulated until 6 and subtract the probability accumulated until the previous integer:
P(X=6)= P(X≤6)-P(X≤5)= 0.2618-0.0856= 0.1762
b. P(9)= P(X=9)
To know the probability of selecting exactly 9 passengers that either rested or slept you have to do the following:
P(X≤9) - P(X≤8)= 1 - 0.8657= 0.1343
c. P(X≥6)
To know what percentage of the probability distribution is above six, you have to subtract from the total probability -1- the cumulated probability until 6 but without including it:
P(X≥6)= 1 - P(X<6)= 1 - P(X≤5)= 1 - 0.0856= 0.9144
I hope it helps!
The U stands for union. Combine A and B
Hope that helps!!
