Data Science Data Science MCQ 3

Question 1

What does a p-value of 0.03 indicate in hypothesis testing at a 0.05 significance level?

Accepted Answer

Reject the null hypothesis

Answer

Accept the null hypothesis as proven true

Answer

The result has no practical significance

Answer

The sample size was too small

Question 2

Which algorithm builds an ensemble of trees sequentially, each correcting the errors of the previous?

Accepted Answer

Gradient boosting

Answer

Random forest

Answer

K-nearest neighbors

Answer

Naive Bayes

Question 3

What is the main advantage of using the F1 score over accuracy?

Accepted Answer

It balances precision and recall, useful for imbalanced classes

Answer

It is always higher than accuracy

Answer

It ignores false negatives

Answer

It requires no ground truth labels

Question 4

In a normal distribution, approximately what percentage of data falls within one standard deviation of the mean?

Accepted Answer

68%

Answer

95%

Answer

50%

Answer

99.7%

Question 5

Which preprocessing step scales features to a range typically between 0 and 1?

Accepted Answer

Min-max normalization

Answer

One-hot encoding

Answer

Label encoding

Answer

Imputation with the mean

Question 6

What problem does the ROC-AUC metric primarily evaluate?

Accepted Answer

A classifier's ability to rank positives above negatives across thresholds

Answer

The training speed of a model

Answer

The variance of the residuals

Answer

The number of clusters in the data

Question 7

Which technique addresses class imbalance by generating synthetic minority-class samples?

Accepted Answer

SMOTE

Answer

PCA

Answer

Dropout

Answer

Batch normalization