# Statistics - Discrete Random Variables- probablility

1.Thirty per cent of all patients undergoing a particular diagnostic procedure require a sedative. In a random sample of 10 patients undergoing the procedure, what is the probability that

a.at least half will require a sedative?

b.fewer then 3 will require a sedative?

c.at least 9 will not require a sedative?

2.The duration of human pregnancies from conception to birth is approximately normally distributed, with a mean of 265 days and a standard deviation of 15 days.

a.What is the probability that the duration of human pregnancy is less than or equal to 228 days?

b.What is the probability that the duration of a human pregnancy exceeds 300 days?

c.What is the probability that the duration of a human pregnancy lasts from 238 days to 299 days?

d.Twenty percent of human pregnancies last more than what amount of time?

3.An airline company knows that 8% of its passengers will not show up for their scheduled flights. A plane has 175 seats.

a.What is the probability that 10 passengers or fewer will not show up?

b.What is the probability that from 10 to 15 passengers will not show up?

c.What is the probability that exactly 10 passengers will not show up?

d.What is the probability that more than 19 passengers will not show up?

https://brainmass.com/statistics/probability/statistics-discrete-random-variables-probablility-213912

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