MS-DS Master of Data science FREE Master of Data Science Research & Data Analysis Questions and Answers 2

Question 1

A data scientist wants to determine whether a new recommendation algorithm increases user engagement compared to the existing one. Which experimental design is most appropriate?

Accepted Answer

A/B testing with random user assignment

Answer

Observational cohort study

Answer

Case-control study

Answer

Time-series analysis without a control group

Question 2

When performing exploratory data analysis on a dataset with 50 features, which technique is most useful for identifying multicollinearity before building a regression model?

Accepted Answer

Variance Inflation Factor (VIF) analysis

Answer

Chi-square test of independence

Answer

Kolmogorov-Smirnov test

Answer

Mann-Whitney U test

Question 3

A researcher notices that their linear regression model has residuals that fan out as predicted values increase. What assumption is being violated?

Accepted Answer

Homoscedasticity

Answer

Normality of residuals

Answer

Independence of observations

Answer

Linearity

Question 4

In a master's thesis analyzing healthcare data, which method best handles missing data when the missingness mechanism is Missing at Random (MAR)?

Accepted Answer

Multiple imputation

Answer

Listwise deletion

Answer

Mean imputation

Answer

Replacing with zero

Question 5

A data science graduate student is presenting research findings and reports a p-value of 0.03 with a confidence interval of [-0.5, 12.3] for the treatment effect. What is the most valid interpretation?

Accepted Answer

The result is statistically significant but the wide interval suggests low practical precision

Answer

The treatment definitely has a positive effect

Answer

The null hypothesis is true with 97% probability

Answer

The treatment effect is exactly 5.9

Question 6

Which cross-validation strategy is most appropriate when working with time-series data in a predictive modeling research project?

Accepted Answer

Time-series split (expanding window) cross-validation

Answer

Standard k-fold cross-validation

Answer

Leave-one-out cross-validation

Answer

Stratified k-fold cross-validation

A data scientist wants to determine whether a new recommendation algorithm increases user engagement compared to the existing one.Which experimental design is most appropriate?

A data scientist wants to determine whether a new recommendation algorithm increases user engagement compared to the existing one.
Which experimental design is most appropriate?