Which of the following is always true for all probability density functions of continuous random variables?
A) They are symmetrical.
B) They are skewed to the right.
C) They are skewed to the left.
D) The area under the curve is 1.0.
E) The area under the curve is 0.1.

Question

Quizplus · Accepted Answer

The area under the curve of a probability density function must be equal to 1, as the entire range of possible outcomes must be accounted for. Option A is not always true, as some probability density functions may be skewed to one side. Option B and C are conflicting statements, and neither are always true for all probability density functions. Option E is incorrect, as the area under the curve must be 1 and not 0.1.

Which of the Following Is Always True for All Probability