Data Science FREE Data Science Analysis Question and Answers 2

Question 1

Which technique is most appropriate for reducing the dimensionality of a dataset while preserving the maximum variance?

Accepted Answer

Principal Component Analysis (PCA)

Answer

K-Means Clustering

Answer

Linear Regression

Answer

Decision Trees

Question 2

In exploratory data analysis, what does a right-skewed distribution indicate about the data?

Accepted Answer

The tail extends toward higher values with most data concentrated on the left

Answer

The data is uniformly distributed

Answer

The mean is less than the median

Answer

The distribution has no outliers

Question 3

When performing A/B testing, what is the primary purpose of calculating statistical power before running the experiment?

Accepted Answer

To determine the minimum sample size needed to detect a meaningful effect

Answer

To calculate the p-value threshold

Answer

To choose between parametric and non-parametric tests

Answer

To measure the effect size after the experiment

Question 4

Which metric is most appropriate for evaluating a classification model when the dataset has a severe class imbalance (e.g., 95% negative, 5% positive)?

Accepted Answer

Area Under the Precision-Recall Curve (AUPRC)

Answer

Accuracy

Answer

R-squared

Answer

Mean Absolute Error

Question 5

What is the main risk of using too many features relative to the number of observations in a regression model?

Accepted Answer

Overfitting, where the model captures noise rather than the true signal

Answer

Underfitting, where the model is too simple

Answer

Increased bias in parameter estimates

Answer

Slower convergence of gradient descent

Question 6

In time series analysis, what does the Augmented Dickey-Fuller (ADF) test assess?

Accepted Answer

Whether the series is stationary or contains a unit root

Answer

Whether the series follows a normal distribution

Answer

Whether two time series are cointegrated

Answer

Whether seasonal patterns are present