Question 1

Which of the following best describes the probability of an impossible event?

Accepted Answer

$$P(A) = 0$$

Question 2

A blood bank has 5 bags of Type A, 3 bags of Type B, and 2 bags of Type O blood. If a bag is selected at random, what is the probability that it is NOT Type B?

Accepted Answer

$$P(	ext{not B}) = \frac{7}{10}$$

Question 3

In a clinical trial, 470 out of 500 patients recovered after receiving a new vaccine. What is the experimental probability that a randomly selected patient recovers?

Accepted Answer

$$P(	ext{recovery}) = \frac{470}{500} = 0.94$$

Question 4

Which of the following is an example of a mutually exclusive event?

Accepted Answer

Drawing a red card and drawing a black card from a deck in the same draw

Question 5

A die is tossed once. What is the probability of getting an even number?

Accepted Answer

$$P(	ext{even}) = \frac{3}{6} = 0.5$$

Question 6

In a population, the probability of having diabetes is 0.2, hypertension is 0.3, and both is 0.1. What is the probability that a randomly selected person has either diabetes or hypertension?

Accepted Answer

$$P(D \cup H) = P(D) + P(H) - P(D \cap H) = 0.2 + 0.3 - 0.1 = 0.4$$

Question 7

A diagnostic test for a rare disease has sensitivity 95% and specificity 90%. The disease prevalence is 1 in 1000. What is the probability that a person who tests positive actually has the disease?

Accepted Answer

$$P(D|T^+) = \frac{(0.95)(0.001)}{(0.95)(0.001) + (0.10)(0.999)} \approx 0.00942$$

Question 8

Which formula represents the Addition Rule for two events A and B?

Accepted Answer

$$P(A \cup B) = P(A) + P(B) - P(A \cap B)$$

Question 9

A COVID-19 test is 95% accurate. If the prevalence of COVID-19 in a population is 5%, what is the probability that a randomly selected person tests positive?

Accepted Answer

$$P(T^+) = (0.95)(0.05) + (0.05)(0.95) = 0.0475 + 0.0475 = 0.095$$

Question 10

Which of the following is an example of independent events?

Accepted Answer

Tossing a coin and rolling a die

Question 11

If $$P(A) = 0.7$$, what is the probability of the complement event $$A'$$?

Accepted Answer

$$P(A') = 0.3$$

Question 12

A box contains 3 red balls and 12 blue balls. What is the probability of randomly selecting a red ball?

Accepted Answer

$$P(	ext{red}) = \frac{3}{15}$$

Question 13

A coin is tossed. What is the probability of getting either a head or a tail?

Accepted Answer

$$P(	ext{head or tail}) = 1$$

Question 14

In a hospital, 30 out of 100 patients have diabetes. If a patient is selected at random, what is the probability that the patient does NOT have diabetes?

Accepted Answer

$$P(	ext{not diabetes}) = \frac{70}{100} = 0.7$$

Question 15

Which of the following statements about probability is TRUE?

Accepted Answer

Probability values always range from 0 to 1

Question 16

A diagnostic test for a disease has sensitivity 98% and specificity 90%. If 10% of the population has the disease, what is the probability that a randomly selected person tests positive?

Accepted Answer

$$P(T^+) = (0.98)(0.10) + (0.10)(0.90) = 0.098 + 0.09 = 0.188$$

Question 17

Which formula is used to calculate conditional probability?

Accepted Answer

$$P(A|B) = \frac{P(A \cap B)}{P(B)}$$

Question 18

Which of the following is a real-world application of probability in health sciences?

Accepted Answer

Estimating the risk of developing chronic diseases

Module 6

Study Guide - Practice Questions

Study Guide - Flashcards