GAT Subject Statistics MCQs

Conditional probability updates the relevant sample space using known information.
It is written as P(A|B).

The addition rule combines probabilities of events in a union.
Any overlap must be subtracted once.

Independence allows multiplication of the separate event probabilities.
This gives the probability that both occur.

Bayes theorem reverses conditional probabilities using prior information.
It combines prior probability with likelihood of evidence.

Permutations count ordered arrangements.
Changing the order produces a different arrangement.

Standard deviation is the square root of variance.
The square root of 25 is 5.

Subtract the mean and divide by the standard deviation.
The z-score is (70 - 50) ÷ 10 = 2.

Use x = mean + z × standard deviation.
Thus x = 80 + (-2)(5) = 70.

Coefficient of variation is SD divided by mean times 100 percent.
CV = 8 ÷ 40 × 100% = 20%.

The value 3 occurs three times, more than any other value.
Therefore, 3 is the mode.

Adding a constant to every value adds the same constant to the mean.
Measures of spread such as standard deviation remain unchanged.

The maximum is 25 and the minimum is 7.
The range is 25 - 7 = 18.