A geologist has collected 10 specimens of basaltic rock and 10 specimens of granite. The geologist instructs a laboratory assistant to randomly select 15 of the speci- mens for analysis. a. What is the pmf of the number of granite specimens selected for analysis

Thus, the pmf of the number of granite specimens selected for analysis is .

Step-by-step explanation:

The experiment consists of collecting rocks.

The sample consisted of, 10 specimens of basaltic rock and 10 specimens of granite.

The total sample is of size, n = 20.

Let the random variable X be defined as the number of granite specimen selected.

The probability of selecting a granite specimen is:

A randomly selected rock can either be basaltic or granite, independently.

The success is defined as the selection of granite rock.

The random variable X follows a Binomial distribution with parameter n = 20 and p = 0.50.

The probability mass function of X is:

the answer is n

walter needs to make at least 5 more cookies but no more than 40. 5 ≤ x ≤ 40

step-by-step explanation:

20 ≤ x + 15 ≤ 55

subtract 15 from all parts

20-15 ≤ x + 15-15 ≤ 55-15

5 ≤ x ≤ 40

this means how many more cookies he has to make

walter needs to make at least 5 more cookies, but no more than 40 cookies; 5 ≤ x ≤ 40