A Biology Professor Responds to Some Student Questions by E-Mail

question 39

Essay

A biology professor responds to some student questions by e-mail. The probability model below describes the number of e-mails that the professor may receive from students during a day.

$\begin{array}{l|c|c|c|c|c|c} \text { E-mails received }& 0 & 1 & 2 & 3 & 4 & 5 \\\hline \text { Probability} & 0.05 & 0.10 & 0.20 & 0.25 & 0.30 & 0.10\end{array}$

a. How many e-mails should the professor expect to receive each day?
b. What is the standard deviation?
c. If it takes the professor an average of ten minutes to respond to each e-mail, how much
time should the professor expect to spend responding to student e-mails each day?

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Definitions:

William Hannibal Thomas

An African American author, soldier, and lawyer, known for his controversial 1901 book "The American Negro."

The American Negro

Historically, a term used to describe African Americans, particularly during periods when racial terminologies were less sensitive.

General Education Board

An organization established by John D. Rockefeller and Frederick T. Gates in 1903 to fund and reform education in the United States, particularly in the South.

Slater Fund

A philanthropic fund established in 1882 by John F. Slater aimed at improving education for African Americans in the southern United States.