Practice Free PCAD-31-02 Exam Online Questions
Which method is used after grouping a DataFrame to compute the average value for each group in a specific column?
- A . groupby().max()
- B . groupby().mean()
- C . groupby().aggregate()
- D . groupby().count()
What is a major challenge in aggregating data from multiple sources?
- A . Excessive disk space usage
- B . Duplicate records and format inconsistencies
- C . Increased algorithmic complexity
- D . Overfitting in predictive models
Which practices help ensure secure and effective execution of SQL queries in Python scripts? (Choose all that apply)
- A . Using string formatting to build SQL queries dynamically
- B . Wrapping SQL commands in try-except blocks
- C . Employing parameterized statements for user-supplied data
- D . Using string concatenation to insert variables into SQL
Which metric is most appropriate for evaluating the accuracy of a classification model?
- A . R-squared
- B . Confusion matrix
- C . Mean squared error
- D . Precision
Which Python library is most commonly used to establish a connection to a SQLite database and perform SQL operations?
- A . pymysql
- B . psycopg2
- C . sqlite3
- D . sqlalchemy
When analyzing a dataset of customer ages, you calculate the mean, median, and mode.
What does it indicate if all three values are approximately equal?
- A . The dataset is uniformly distributed
- B . The dataset is positively skewed
- C . The dataset has a normal distribution
- D . The dataset contains outliers
What does a Pearson correlation coefficient value of -0.9 imply about the relationship between two numerical variables?
- A . No correlation
- B . A weak positive relationship
- C . A strong negative linear relationship
- D . A moderate non-linear association
Which of the following libraries is specifically optimized for high-performance numerical computation with multi-dimensional arrays in Python?
- A . matplotlib
- B . pandas
- C . NumPy
- D . seaborn
Which Pandas methods are commonly used to extract central tendency and dispersion insights from a DataFrame? (choose two)
- A . median()
- B . sort_values()
- C . var()
- D . pivot_table()
Which Python tool or library is best suited for retrieving data from HTML tables on web pages?
- A . re
- B . pandas.read_html()
- C . math
- D . sqlalchemy