CLAST Statistics and Probability 3

Question 1

A stem-and-leaf plot shows stems 2, 3, 4 with leaves 2|1 5, 3|0 3 8, 4|2. What is the range of the data set?

Accepted Answer

21

Answer

The maximum value is 42 and the minimum is 21, so the range = 42 − 21 = 21.

Question 2

Events A and B are mutually exclusive. P(A) = 0.4 and P(B) = 0.25. What is P(A or B)?

Accepted Answer

0.65

Answer

For mutually exclusive events, P(A or B) = P(A) + P(B) = 0.4 + 0.25 = 0.65.

Question 3

A frequency table shows: Score 70 (freq 4), 80 (freq 6), 90 (freq 2). What is the mean score?

Accepted Answer

78.3

Answer

Mean = (70×4 + 80×6 + 90×2) / (4+6+2) = (280+480+180)/12 = 940/12 ≈ 78.3.

Question 4

Which type of graph is BEST suited to display how a quantity changes over time?

Accepted Answer

Line graph

Answer

Line graphs are specifically designed to show trends and changes in data over time.

Question 5

Two fair coins are flipped. What is the probability of getting exactly one head?

Accepted Answer

1/2

Answer

The sample space is {HH, HT, TH, TT}; exactly one head occurs in 2 of 4 outcomes, so P = 2/4 = 1/2.

CLAST - College Level Academic Skills Test Practice Test