Q: A box contains 8 pens, 5 of which are blue. If two pens are drawn one after another without replacement, what is the probability both are blue?

$$\frac{5}{8} \times \frac{4}{7}$$

Question 1

Which of the following best describes a confounding variable in an experiment?

Accepted Answer

A variable that cannot be distinguished from the effects of other factors on the outcome.

Question 2

A pharmaceutical company is testing a new drug. Neither the patients nor the doctors know who receives the drug or a placebo until after the study is complete. What type of experimental design is this?

Accepted Answer

Double-blind experiment

Question 3

Which formula should you use to determine the number of ways to arrange 5 books on a shelf?

Accepted Answer

$$5!$$

Question 4

A researcher wants to select a committee of 4 students from a class of 10. In how many ways can this be done?

Accepted Answer

$$C(10,4) = \frac{10!}{4!(10-4)!}$$

Question 5

If the probability of rain tomorrow is $$0.3$$, what is the probability that it will NOT rain?

Accepted Answer

$$0.7$$

Question 6

A bag contains 4 red, 5 blue, and 3 green marbles. If one marble is drawn at random, what is the probability it is blue?

Accepted Answer

$$\frac{5}{12}$$

Question 7

Which of the following is an example of qualitative data?

Accepted Answer

The colors of cars in a parking lot

Question 8

A coin is flipped and a die is rolled. What is the probability of getting heads and a 6?

Accepted Answer

$$\frac{1}{12}$$

Question 9

Which of the following best describes inferential statistics?

Accepted Answer

Using a sample to draw conclusions about a population

Question 10

A deck of 52 cards is shuffled. What is the probability of drawing a heart or a king?

Accepted Answer

$$\frac{16}{52}$$

Question 11

Which of the following is NOT a key element of a well-designed experiment?

Accepted Answer

Bias

Question 12

If $$P(A) = 0.4$$ and $$P(B) = 0.5$$, and A and B are independent, what is $$P(A 	ext{ and } B)$$?

Accepted Answer

$$0.2$$

Question 13

A password consists of 2 letters followed by 3 digits. How many different passwords are possible if letters and digits can be repeated?

Accepted Answer

$$26^2$$ 	imes $$10^3$$

Question 14

Which of the following statements about the normal distribution is FALSE?

Accepted Answer

The standard normal distribution has a mean of 1 and standard deviation of 0.

Question 15

A survey asks 100 randomly selected people if they prefer coffee or tea. What type of data collection method is this?

Accepted Answer

Survey

Question 16

If the odds in favor of an event are 3:5, what is the probability of the event?

Accepted Answer

$$\frac{3}{8}$$

Question 17

Which of the following is a parameter?

Accepted Answer

The average height of all students in a university

Question 18

A box contains 8 pens, 5 of which are blue. If two pens are drawn one after another without replacement, what is the probability both are blue?

Accepted Answer

$$\frac{5}{8} 	imes \frac{4}{7}$$

Question 19

Which formula gives the probability of event B occurring given that event A has already occurred?

Accepted Answer

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

Question 20

A researcher wants to know the effect of a new fertilizer on plant growth. She applies the fertilizer to half the plants and leaves the other half untreated. She then compares the growth of both groups. What type of study is this?

Accepted Answer

Experiment

Foundations of Statistics: Data Types, Probability, and Counting Principles

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