MCQ for Data Analyst

51. What is a decision tree in machine learning?

A method to visualize time series data
A model that makes decisions by splitting data into branches
A clustering algorithm
A method for scaling features

52. What is a confusion matrix in classification problems?

A matrix that stores missing data
A table showing the true positives, true negatives, false positives, and false negatives
A method to calculate correlation
A clustering method

53. What does R-squared measure in regression analysis?

The slope of the regression line
The proportion of variance in the dependent variable explained by the independent variables
The correlation between two variables
The difference between predicted and actual values

54. What is the difference between classification and regression in machine learning?

Classification predicts categories; regression predicts continuous values
Classification predicts continuous values; regression predicts categories
They are the same
Regression is only used for clustering

55. In a linear regression model, what is the slope?

The y-intercept
The rate of change of the dependent variable with respect to the independent variable
The value of the dependent variable
The difference between predicted and actual values

56. What is cross-validation in machine learning?

A method to increase model complexity
A technique for assessing how a model will generalize to an independent dataset
A way to split the dataset
A type of data augmentation

57. What does normalization in a dataset refer to?

Removing missing values
Scaling data so that values fall within a specific range
Grouping data into categories
Adding outliers

58. What is overfitting in machine learning?

When a model fits the training data too closely and fails to generalize
When a model is too simple
When a model performs well on unseen data
When a model uses too few features

59. What is the purpose of principal component analysis (PCA)?

To increase the number of features
To reduce the dimensionality of the data by transforming features
To add new features
To improve the accuracy of the model

60. What is a random forest in machine learning?

A type of clustering algorithm
An ensemble of decision trees
A technique for feature scaling
A visualization tool