Statistics Flashcards

A dataset has a mean of 50 and a standard deviation of 5. What is the z-score for a value of 60?

Answer: 2.0

z = (60 - 50) / 5 = 2.0.

Which measure of central tendency is most affected by extreme outliers?

Answer: Mean

The mean is pulled toward extreme values because it uses all data points arithmetically.

In a hypothesis test, a Type II error occurs when you:

Answer: Fail to reject a false null hypothesis

A Type II error (beta) is failing to detect a real effect — accepting a false null hypothesis.

Which of the following correlation coefficients indicates the strongest linear relationship?

Answer: r = -0.82

The strength of a correlation depends on the absolute value; |-0.82| = 0.82 is the largest here.

A probability distribution in which every outcome is equally likely is called a:

Answer: Uniform distribution

A uniform distribution assigns equal probability to all outcomes.

The interquartile range (IQR) is calculated as:

Answer: Q3 - Q1

IQR = Q3 - Q1, representing the spread of the middle 50% of data.

If P(A) = 0.4 and P(B) = 0.3 and A and B are independent, what is P(A and B)?

Answer: 0.12

For independent events, P(A and B) = P(A) × P(B) = 0.4 × 0.3 = 0.12.