Chapter 6.1, Problem 1.1CYU

To determine

To explain: The meaning of $P\left(X\ge 3\right)$ in words. Also, find the probability

Answer to Problem 1.1CYU

The probability is 0.727.

Explanation of Solution

Given:

The table is:

Values	0	1	2	3	4
Probability	0.011	0.032	?	0.362	0.457

Calculation:

To explain the term, the missing value is required to be computed. Let the missing value be x .

The missing value can be calculated as:

  $\begin{array}{c}0.011+0.032+x+0.362+0.457=1\\ x+0.862=1\\ x=0.138\end{array}$

  $P\left(X\ge 3\right)$ can be calculated as:

  $\begin{array}{c}P\left(X\ge 3\right)=P\left(X=3\right)+P\left(X=4\right)\\ =0.362+0.457\\ =0.819\end{array}$

The required probability is 0.819.

  $P\left(X\ge 3\right)$ represents the probability that student will get a B or more.