Answer:
(b)$29.62
(c)$5.73
Explanation:
Basic: Standard internet for everyday needs, at $24.95 per month.
Premium: Fast internet speeds for streaming video and downloading music, at $30.95 per month.
Ultra: Super-fast internet speeds for online gaming at $40.95 per month.
Let the number of customers on Ultra=x; therefore:
Number of Premium customers =2x
Number of Basic customers =3x
Total=x+2x+3x=6x
![P(Ultra)=(x)/(6x)=(1)/(6) \\P(Premium)=(2x)/(6x)=(1)/(3)\\P(Basic)=(3x)/(6x)=(1)/(2)](https://img.qammunity.org/2021/formulas/mathematics/college/y4d34cybtwpq2md9sv8k4i5h1j452ygu48.png)
(a)X=Monthly fee paid by a randomly selected customer.
Therefore, the probability distribution of X is given as:
![\left|\begin{array}cX&P(X)\\---&---\\\$24.95&3/6\\\$30.95&2/6\\\$40.95&1/6\end{array}\right|](https://img.qammunity.org/2021/formulas/mathematics/college/vidl4xxh1d4of1n1jhnp4laqtduygy62ee.png)
(b)Average Monthly Revenue per customer
Mean,
![\mu=(\$24.95 * 3/6)+(\$30.95 * 2/6)+(\$40.95 * 1/6)\\=\$29.62](https://img.qammunity.org/2021/formulas/mathematics/college/vu82gsv5e22tr2pzobdwwofbof3cfvknln.png)
(c)Standard Deviation
![\left|\begin{array}cx&P(x)&x-\mu &(x-\mu)^2&(x-\mu)^2P(x)\\-----&-----&----&----&-----\\\$24.95&3/6&-4.67&21.8089&10.9045\\\$30.95&2/6&1.33&1.7689&0.5896\\\$40.95&1/6&11.33&128.3689&21.3948\\-----&-----&----&----&-----\\&&&&32.8889\end{array}\right|](https://img.qammunity.org/2021/formulas/mathematics/college/buo0q9v4lgewy4vzi5tas8zmx3lxp1j827.png)
![\text{Standard Deviation}=√((x-\mu)^2P(x))\\=√(32.8889) \\ \sigma=\$5.73](https://img.qammunity.org/2021/formulas/mathematics/college/sree3ghp5jbr64miyx2kv2q0oaz3yigaxm.png)