UGC NET Questions (Paper – 1)

The normal distribution is a theoretical, continuous probability distribution that is symmetric around its mean and has a characteristic bell shape. Many natural and measurement-related variables approximate this form under suitable conditions. In a normal distribution, fixed proportions of scores fall within one, two or three standard deviations of the mean. Therefore, the symmetric bell-shaped distribution described in the stem is correctly called the normal distribution.

Option A:
The binomial distribution deals with discrete outcomes of a fixed number of trials with two possible results, such as success and failure, and is not continuous or bell-shaped in the same way.

Option B:
The normal distribution underlies many parametric statistical tests and allows use of z-scores and confidence intervals. Its shape is fully determined by its mean and standard deviation, matching the stem exactly and making this option correct.

Option C:
The Poisson distribution models counts of rare events over space or time and is typically skewed, especially at low expected counts, not symmetric and bell-shaped like the normal.

Option D:
A skewed distribution is any distribution lacking symmetry, often with one tail longer than the other, which contradicts the symmetric property stated in the question.