Uncategorized Data Analyst screening Test by mfh.officials@gmail.com Jan 17, 2025 0 Comment Data Analyst Screening Test 1 / 20 Which statistical test is commonly used to compare means of two groups? Regression analysis t-test ANOVA Chi-square test 2 / 20 When should you use a boxplot? To display the frequency of categories. To calculate probabilities. To identify relationships between variables. To compare distributions between groups. 3 / 20 Which metric is commonly used to evaluate regression models? R-squared Accuracy Confusion Matrix Precision 4 / 20 Which method is best for handling outliers in a dataset? Replace with the mean or median Drop them All of the above Transform data using log or square root 5 / 20 In a classification problem, which metric indicates the balance between precision and recall? ROC Curve F1-Score Accuracy Mean Squared Error 6 / 20 What does one-hot encoding do in data preprocessing? Normalizes numerical features. Creates a summary of the dataset. Converts categorical variables into numerical form. Removes duplicate data. 7 / 20 Which machine learning library is used for building predictive models in Python? Pandas Matplotlib Scikit-learn NumPy 8 / 20 Which technique is used to reduce the dimensions of a dataset? Data sampling K-Means Clustering Normalization Principal Component Analysis (PCA) 9 / 20 Which measure indicates the spread of data in a dataset? Mean Median Mode Variance 10 / 20 What is overfitting in machine learning? When the model generalizes well on unseen data. When the model performs exceptionally well on training data but poorly on test data. When the model fails to train completely. When the model performs poorly on training data but well on test data. 11 / 20 In Power BI, what does DAX stand for? Data Assessment Extension Data Analysis Expression Data Analytics Execution Data Aggregation Expression 12 / 20 In Python’s pandas library, which method is used to merge DataFrames on a common key? df.concat() df.append() df.join() df.merge() 13 / 20 What does the p-value in a hypothesis test represent? a) The probability of rejecting the null hypothesis when it's trued. The probability of observing the data, given that the null hypothesis is true. The margin of error in the dataset. The confidence level of the hypothesis. 14 / 20 Which visualization tool is primarily used for creating dashboards? NumPy Matplotlib Scikit-learn Tableau 15 / 20 What is the purpose of standardization in data preprocessing? To scale data to a fixed range. To identify outliers. To make data have a mean of 0 and standard deviation of 1 To remove missing values. 16 / 20 Which of the following is a feature of NoSQL databases like MongoDB? Relational structure Schema-based Scalability and flexibility Fixed data types 17 / 20 What type of machine learning algorithm is K-Means? Reinforcement Semi-supervised Unsupervised Supervised 18 / 20 Which SQL command is used to remove rows from a table? DELETE REMOVE DROP TRUNCATE 19 / 20 What does it mean when a dataset is said to have “missing data”? Some values are undefined or absent. Duplicate rows exist. Columns have the same values. Values are in the wrong format. 20 / 20 Which correlation coefficient represents the strongest relationship? 0 0.85 -0.5 -0.95 Your score is
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