# Probability (ISS (Statistical Services) Statistics Paper I (New 2016 MCQ Pattern)): Questions 84 - 86 of 205

Get 1 year subscription: Access detailed explanations (illustrated with images and videos) to 469 questions. Access all new questions we will add tracking exam-pattern and syllabus changes. View Sample Explanation or View Features.

Rs. 300.00 or

## Question number: 84

» Probability » Bayes' Theorem and Applications

MCQ▾

### Question

Suppose a certain drug test is 99 % sensitive and 99 % specific, that is, the test will correctly identify a drug user as testing positive 99 % of the time, and will correctly identify a non-user as testing negative 99 % of the time. Let’s assume a corporation decides to test its employees for drug use, and that only 0.5 % of the employees actually use the drug. The probability that, given a positive drug test, an employee is actually a drug user is conducted using Bayes’ theorem. Can we say Bayes’ theorem gives correct result?

### Choices

Choice (4) Response

a.

Information insufficient

b.

Yes always

c.

Not always

d.

Can’t make any claim

## Question number: 85

» Probability » Probability Distributions » Negative Binomial

MCQ▾

### Question

In a sequence of independent Bernoulli trails, if denotes the number of failures before (fixed) success, then the expected value of will be ________

### Choices

Choice (4) Response

a.

b.

c.

d.

Question does not provide sufficient data or is vague

## Question number: 86

» Probability » Probability Distributions » Poisson

MCQ▾

### Question

Twenty sheets of copper alloy were examined for surface flaws. The frequency of the number of sheets with a given number of flaws per sheet was as follows:

 Number of flaws Frequency 0 4 1 3 2 5 3 2 4 4 5 1

What is the probability of finding a sheet chosen at random which contains 3 or more surface flaws?

### Choices

Choice (4) Response

a.

b.

c.

d.

Question does not provide sufficient data or is vague

f Page