DAC DAC Statistical Methods & Analytics 2

Question 1

What is the difference between a population and a sample in statistics?

Accepted Answer

A population includes all members of a group; a sample is a subset selected for study

Answer

A population is always smaller than a sample

Answer

A sample is the entire group of interest; a population is a subset used for testing

Answer

There is no meaningful difference between the two terms

Question 2

Which statistical test is appropriate for comparing the means of two independent groups?

Accepted Answer

Independent samples t-test

Answer

Chi-square test

Answer

Pearson correlation

Answer

ANOVA

Question 3

What does a positively skewed distribution indicate about the data?

Accepted Answer

Most values are concentrated on the left side with a long right tail

Answer

Most values are concentrated on the right side with a long left tail

Answer

The mean equals the median

Answer

The data has no outliers

Question 4

In regression analysis, what does the R-squared value represent?

Accepted Answer

The proportion of variance in the dependent variable explained by the independent variables

Answer

The slope of the regression line

Answer

The number of variables in the model

Answer

The significance of individual predictors

Question 5

What is the purpose of ANOVA (Analysis of Variance)?

Accepted Answer

To compare the means of three or more groups simultaneously

Answer

To measure the correlation between two variables

Answer

To test the normality of a dataset

Answer

To calculate the standard deviation of a sample

Question 6

Which probability distribution is symmetric and bell-shaped, often used as a basis for statistical inference?

Accepted Answer

Normal distribution

Answer

Poisson distribution

Answer

Exponential distribution

Answer

Binomial distribution