In: Statistics and Probability
It is advisable to have working smoke detectors in your
apartment. In fact, JJ Smoke Detectors Advisors (JJSDA) analyzes
the numbers of smoke detectors in apartments. Suppose X is the
number of smoke detectors in a randomly selected apartment. Then
according to JJSDA, x has the following probability mass function,
p(x), and cumulative distribution function F(x).
x | 0 | 1 | 2 | 3 | 4 | 5 |
p(x) | .119 | .171 | .35 | .20 | b | .03 |
F(x) | .119 | a | .640 | .840 | .970 | 1.00 |
a. If F is the cumulative distribution function of x, then what is
the value of a?
b. If p is the probability mass function for x, then evaluate b. c)
What is the expected value of x <_>
c. What is the expected value of x?
d. Calculate the standard deviation of x.
e. What is the variance of .5x?
f. JJSDA checks 9 apartments on a Tuesday. What is the probability
that there are exactly 3 smoke detectors in exactly 3 of the
checked apartments?
g. JJSDA checks 5 apartments on a Wednesday. What is the
probability that all 5 of those apartments have at least 2 smoke
detectors?
h.What is the expected value of
x3
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