ALEKS Statistics and Probability 3

Question 1

A data set has mean 50 and standard deviation 5. What percentage of data falls within one standard deviation of the mean (using the empirical rule)?

Accepted Answer

68%

Answer

The empirical rule states approximately 68% of data falls within one standard deviation of the mean.

Question 2

What is the probability of two independent events both occurring if P(A) = 0.4 and P(B) = 0.5?

Accepted Answer

0.20

Answer

For independent events, P(A and B) = P(A) × P(B) = 0.4 × 0.5 = 0.20.

Question 3

Which value represents the middle 50% of a data set in a box plot?

Accepted Answer

Interquartile range (IQR)

Answer

The IQR is the difference between Q3 and Q1, representing the spread of the middle 50% of data.

Question 4

A survey of 200 people found 60 prefer brand A. What is the relative frequency of brand A preference?

Accepted Answer

0.30

Answer

Relative frequency = 60/200 = 0.30.

Question 5

What is the probability of NOT rolling a 6 on a fair die?

Accepted Answer

5/6

Answer

P(not 6) = 1 - P(6) = 1 - 1/6 = 5/6.

ALEKS - Assessment and Learning in Knowledge Spaces Practice Test