Chapter 1.1, Problem 28E

(a)

To determine

To calculate the proportion of invisibility given that from United States.

Answer to Problem 28E

The required proportion = 0.1721

Explanation of Solution

Given:

The Dataset:

		Country
		U.K.	U.S.
	Fly	54	45
	Freeze time	52	44
Superpower	Invisibility	30	37
	Super strength	20	23
	Telepathy	44	66

Calculation:

  $\begin{array}{c}\text{P}\left(\text{Invisibility | United States}\right)=\frac{\text{P}\left(\text{Invisibility}\text{and United States}\right)}{\text{P }\left(\text{United States}\right)}\\ =\frac{37}{215}\\ =0.1721\end{array}$

(b)

To determine

To calculate the proportion of Super strength given that from United Kingdom.

Answer to Problem 28E

The required proportion = 0.10

Explanation of Solution

Calculation:

  $\begin{array}{c}\text{P}\left(\text{Super strength}|\text{United Kingdom}\right)=\frac{\text{P}\left(\text{Super strength}|\text{United Kingdom}\right)}{\text{P }\left(\text{United Kingdom}\right)}\\ =\frac{20}{200}\\ =0.10\end{array}$