Probability - Aptitude MCQ Questions and Solutions with Explanations

p > $$\frac{{1}}{{2}}$$
If p < 0.5, then the distribution is positively skewed.
If p > 0.5, the distribution is negatively skewed

Probability that A is telling the truth P(A)
= $$\frac{{75}}{{100}}$$ = $$\frac{{3}}{{4}}$$
Probability that B is telling the truth P(B)
= $$\frac{{80}}{{100}}$$ = $$\frac{{4}}{{5}}$$
Probability that A is lying P(A’)
= 1 - $$\frac{{75}}{{100}}$$ = $$\frac{{25}}{{100}}$$ = $$\frac{{1}}{{4}}$$
Probability that B is lying P(B’)
= 1 - $$\frac{{80}}{{100}}$$ = $$\frac{{20}}{{100}}$$ = $$\frac{{1}}{{5}}$$
Contradiction means either of
A telling truth and B lying
            Or
B telling truth and A lying
P(Contradiction)
= P(A) × P(B’) + P(A’) × P(B)
= $$\frac{{3}}{{4}}$$ × $$\frac{{1}}{{5}}$$ + $$\frac{{1}}{{4}}$$ × $$\frac{{4}}{{5}}$$
= $$\frac{{7}}{{20}}$$
$$\frac{{7}}{{20}}$$ is equal to 35 %.

Two events are mutually exclusive if they (both of them) cannot occur together.

Probability distribution is listing of the all possible outcomes from an experiment with their associated probability for each outcome.

Probability is measure of uncertainty its not collection of several experiments.

In special rule of addition of probability the events must be mutually exclusive.

Binomial distribution has 2 parameters

The variance of binomial distribution is always Less than mean

In Classical probability the outcomes are equally likely to occur.

must have at least 3 trials