MS-DS Master of Data science FREE Master of Data Science Research & Data Analysis Questions and Answers 3

Question 1

A data science researcher is choosing between Ridge and Lasso regression for a high-dimensional dataset. What is the key distinguishing behavior of Lasso?

Accepted Answer

It can shrink coefficients exactly to zero, performing feature selection

Answer

It penalizes the sum of squared coefficients

Answer

It always produces lower bias than Ridge

Answer

It requires normally distributed predictors

Question 2

In a research study, a graduate student computes a Pearson correlation of 0.85 between two variables. Which additional analysis should they perform before concluding a strong linear relationship?

Accepted Answer

Check a scatterplot for outliers and nonlinear patterns

Answer

Compute the mean of both variables

Answer

Run a chi-square test

Answer

Calculate the mode of the residuals

Question 3

Which sampling method should a data science researcher use to ensure that subgroups in a population are proportionally represented in the sample?

Accepted Answer

Stratified random sampling

Answer

Simple random sampling

Answer

Convenience sampling

Answer

Snowball sampling

Question 4

A master's student is building a classification model and notices the AUC-ROC is 0.95 on training data but 0.61 on the test set. What does this most likely indicate?

Accepted Answer

The model is overfitting to the training data

Answer

The model is underfitting the data

Answer

The test set has label errors

Answer

The features are not predictive

Question 5

When conducting a literature review for a data science thesis, which database is most specialized for computer science and data science research papers?

Accepted Answer

IEEE Xplore and ACM Digital Library

Answer

PubMed

Answer

JSTOR

Answer

LexisNexis

Question 6

A researcher applies Principal Component Analysis to a dataset with 20 standardized features and finds that the first three components explain 85% of total variance. What is the best next step?

Accepted Answer

Retain the first three components and examine their loadings to interpret the underlying structure

Answer

Discard PCA and use all 20 features

Answer

Use only the first component since it explains the most variance

Answer

Automatically select components with eigenvalues below 1