## Find the probability mass function of X

1.  Determine whether each of the following random variables is discrete or continuous.

a.  The number of heads in 100 tosses of a coin.

b.  The length of a rod randomly chosen from a day's production.

c.   The final exam score of a randomly chosen student from last semester's engineering statistics class.

d.  The age of a randomly chosen Colorado School of Mines student.

e.  The age that a randomly chosen Colorado School of Mines student will be on his or her next birthday.

2.   A survey of cars on a certain stretch of highway during morning commute hours showed that 70% had only one occupant, 15% had 2, 10% had 3, 3% had 4, and 2% had 5. Let X represent the number of occupants in a randomly chosen car.

a.  Find the probability mass function of X

b.  . Find P(X ≤ 2).

c.   Find P(X > 3).

d.  Find μX .

e.  Find σX .

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