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 the complete set of all individuals or items of interest, while a sample is a smaller subset drawn from the population for analysis.

Question 2

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

Accepted Answer

Independent samples t-test

Answer

The independent samples t-test compares the means of two unrelated groups to determine if there is a statistically significant difference.

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

In a positively skewed distribution, the tail extends to the right, meaning most data values are lower but a few extreme high values pull the mean upward.

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

R-squared (coefficient of determination) measures the proportion of variance in the outcome variable that is explained by the predictor variables in the model.

Question 5

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

Accepted Answer

To compare the means of three or more groups simultaneously

Answer

ANOVA tests whether the means of three or more independent groups are statistically different from each other, using variance within and between groups.

Data Analytics Certifications (DAC) Practice Test

Data Analytics Certifications (DAC) Practice Test

DAC DAC Statistical Methods & Analytics 2