Question

7. Events A and B are independent. The P(A) = 3/5, P(not B) = 2/3. What is P(A and B)? a. 2/5 b. 1/5 c. 4/15 d. 2/15

8. A bag contains 4 red marbles, 3 blue marbles, and 7 green marbles. If a marble is randomly selected from the bag, what is the probability that it is blue? A) 1/11 B) 3/14 C) 1/7 D) 1/3

9. The distribution of the heights of students in a large class is roughly bell-shaped. The average height is 68 inches, and approximately 95% of the heights are between 62 and 74 inches. Thus, the standard deviation of the height distribution is approximately: A) 2 B)3 C) 6 D) 9 E) 12

10. If you blindfolded yourself and randomly guessed at three multiple-choice questions with 5 choices, what is the probability you get all 3 correct? A) .008 B) .20 C) .04 D) .08 E) .018

Answer 1

7. Here it is given that

So

Now as we know that for independent events

So answer is b.

8. Here it is given that to total number of marbles is 14

As per definition of probability, probability is favorable number/total number

Now we need to find P(Blue)=No. of blues marbles/Total numbers=

So answer is B.

8. Here it is given that distribution is normal

Also LCI=62 and UCI=74

Now

So

Hence Margin of Error = E=6

Now

So

As z value for 95% CI is 1.96

So

So answer is B.3

10. This is case of biinomial distribution as n=3 is constant, p=0.2 is same for all, only two outcomes and events are independent

So

Hence answer is A. 0.008