ISAT Probability and Statistical Analysis 5

Question 1

In a sample of 200 students, 80 play sports. What is the relative frequency of students who play sports?

Accepted Answer

40%

Answer

80%

Answer

20%

Answer

60%

Question 2

A probability distribution has E(X) = 5 and Var(X) = 4. What is the standard deviation of X?

Accepted Answer

2

Answer

4

Answer

16

Answer

√5

Question 3

Bayes' theorem is used to:

Accepted Answer

Update probability based on new evidence

Answer

Calculate the mean of a distribution

Answer

Find the standard deviation of a sample

Answer

Determine if events are mutually exclusive

Question 4

A data set: 3, 7, 7, 9, 11. What is the mode?

Accepted Answer

7

Answer

9

Answer

3

Answer

11

Question 5

If P(A) = 0.4 and P(A|B) = 0.4, what can be concluded about events A and B?

Accepted Answer

A and B are independent

Answer

A and B are mutually exclusive

Answer

B is a subset of A

Answer

A and B are complementary

Question 6

A researcher records heights of 500 students. The distribution is approximately normal with mean 170 cm and SD 8 cm. About how many students are between 162 cm and 178 cm?

Accepted Answer

340

Answer

475

Answer

250

Answer

400

Question 7

Which of the following is an example of a continuous random variable?

Accepted Answer

The exact temperature at noon

Answer

Number of heads in 10 coin flips

Answer

Number of students in a class

Answer

Number of cars in a parking lot