Chapter PIV, Problem 39RE

(a)

To determine

To find: the what quantity is estimated by the 1^st product $N.f_p$ .

Explanation of Solution

Given:

  

Calculation:

The first product, N # fpthe scope of the number of stars is given in the milky way that planets have.

It is estimated as:

  $\begin{array}{c}N\ast f_p=\left(200\ast 20\%\right)-\left(400\ast 50\%\right)\\ N\ast f_p=\left(200\times \frac{20}{100}\right)-\left(400\times \frac{50}{100}\right)\\ N\ast f_p=\left(40\right)-\left(200\right)\end{array}$

(b)

To determine

To find: the quantity is estimated by the product, $N.f_p.n_e.f_l$

Explanation of Solution

Given:

  

Calculation:

The product, N # fp # ne # fl provides the scope of the number of stars with a suitable atmosphere in the milky way that has planets able to sustain earth-type life.

It is estimated as:

  $\begin{array}{c}N\ast f_p\ast n_e\ast f_l=\left(40-200\right)\ast \left(1-2\right)\ast \left(1\%-100\%\right)\\ =\left(40\times 1\times 1\%\right)-\left(200\times 2\times 100\%\right)\\ =\left(40\times 1\times \frac{1}{100}\right)-\left(200\times 2\times \frac{100}{100}\right)\\ =\left(0.4-400\right)\end{array}$

(c)

To determine

To Calculate:the probability is estimated by the product $f_l.f_i$ .

Explanation of Solution

Given:

  

The probability determined by the product fl # fi is the probability that with the development of intelligence, life evolves on a planet.

(d)

To determine

To find: conditional probabilities are the factors in the formula and restate it in a way that makes the situation simple.

Explanation of Solution

Given:

  

Based on the occurrence of a previous event or outcome, conditional probability is characterized as the probability of an event or outcome occurring. The conditional probability is determined by combining the probability of a preceding event with the modified probability of a good or conditional event.

 So, $f_c$ is the element which is a conditional probability in the formula.

Since the possibility of intelligent life developing radio contact depends on the likelihood of intelligent forms of life.