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