TSI Probabilistic and Statistical Reasoning

Question 1

What is the median of the data set 3, 9, 4, 7, 17?

Accepted Answer

7

Answer

In order, the values are 3, 4, 7, 9, 17. The median is the middle value, 7. The mean is 8 and the range is 14.

Question 2

A bag holds 4 red marbles and 6 blue marbles. If one marble is drawn at random, what is the probability that it is red?

Accepted Answer

2/5

Answer

Probability = favorable outcomes ÷ total outcomes = 4 ÷ 10 = 2/5.

Question 3

Two fair coins are tossed. What is the probability that both land heads?

Accepted Answer

1/4

Answer

The tosses are independent, so P(H and H) = 1/2 × 1/2 = 1/4. The equally likely outcomes are HH, HT, TH and TT.

Question 4

A student's mean score on 5 tests is 82. Four of the scores are 80, 85, 78 and 90. What is the fifth score?

Accepted Answer

77

Answer

The five scores must total 5 × 82 = 410. The four known scores total 333, so the fifth score is 410 − 333 = 77.

Question 5

On a scatter plot of hours studied (x) and test score (y), the points trend upward from left to right. Which statement best describes the relationship?

Accepted Answer

There is a positive correlation

Answer

When y tends to increase as x increases, the correlation is positive. Correlation alone does not prove causation, so the last choice is too strong.

TSI Practice Test

TSI Practice Test

TSI Probabilistic and Statistical Reasoning