This section first defines discrete and continuous random variables. Then, it introduces the distributions for discrete random variables. It also talks about the mean and variance calculations.
1.
a. no: the sum of the probabilities exceeds 1
b. no: a negative probability
c. no: the sum of the probabilities is less than 1
3.
a. 0.4
b. 0.1
c. 0.9
d. 79.15
e. \(σ2=1.5275\)
f. \(σ = 1.2359\)
5.
a. 0.6528
b. 0.7153
c. \(μ = 7.8333\)
d. \(σ2=5.4866\)
e. \(σ = 2.3424\)
7.
a. 0.79
b. 0.60
c. \(μ = 5.8, σ = 1.2570\)
9.
\(\begin{align*}
\begin{array}{c|cccc}
x & 0 & 1 & 2 & 3 \\
\hline P(x) & 1 / 8 & 3 / 8 & 3 / 8 & 1 / 8
\end{array}
\end{align*}\)
11.
a.
\(\begin{align*}
\begin{array}{c|cccc}
x & -1 & 999 & 499 & 99 \\
\hline P(x) & \frac{4987}{5000} & \frac{1}{5000} & \frac{2}{5000} & \frac{10}{5000}
\end{array}
\end{align*}\)
b. −0.4
c. 17.8785
13. 136
15.
a.
\(\begin{align*}\begin{array}{c|cc}
x & C & C-150,000 \\
\hline P(x) & 0.9825 & 0.0175
\end{array}
\end{align*}\)b. \(C−2625\)
c. \(C ≥ 2625\)
d. \(C ≥ 2875\)
17.
a.
\(\begin{align*}b. \(E(X)=−0.0526\) In many bets the bettor sustains an average loss of about 5.25 cents per bet.
c. 0.9986
19.
a. 43.54
b. 1.2046
21. 101.02
23.
a.
\(\begin{align*}b. 1.9444
c. 1.4326
25.
a.
b. 0.902
27.
a. 2523.25
b. 227,092.5
c. 270,000
d. The owner will install the cover.