Interview Questions and Answers

Population refers to the entire group under study, while a sample is a subset of the population.

Example:

Population: All students in a university. Sample: 100 students randomly selected from the university.

The p-value is the probability of obtaining results as extreme as or more extreme than the observed results under the assumption that the null hypothesis is true.

Example:

If p-value is 0.05, there is a 5% chance of observing the results if the null hypothesis is true.

Standard deviation is a measure of the amount of variation or dispersion in a set of values. It represents the average distance of each data point from the mean.

Example:

For a set of test scores: 70, 72, 75, 78, 80. Standard deviation is approximately 3.16.

A population parameter is a numerical value that describes a characteristic of an entire population. A sample statistic is a numerical value that describes a characteristic of a sample drawn from that population.

Example:

Population parameter: Average income of all households. Sample statistic: Average income of a sample of 100 households.

The confidence level is the probability that the calculated confidence interval contains the true population parameter. Common confidence levels are 90%, 95%, and 99%.

Example:

A 99% confidence interval for the average weight of a certain species of bird is 20 to 25 grams.

A histogram is a graphical representation of the distribution of a dataset. It displays the frequencies of different ranges or bins of the data, providing insights into its shape and central tendency.

Example:

Creating a histogram to visualize the distribution of exam scores in a class.

A box plot is used to display the distribution and spread of a dataset. It shows the median, quartiles, and potential outliers in a compact visual format.

Example:

Comparing the distribution of salaries in different departments using box plots.