Data Analysis with Pandas and NumPy PCAD-31 Practice Questions (Page 5)

Questions 21–25

1. 21foundation · easy

   Which Pandas method is used to compute the mean of all numeric columns in a DataFrame?

   • Adf.count()
   • Bdf.sum()
   • Cdf.mean()
   • Ddf.median()
   Reveal Solution Discussion Select an answer first
2. 22foundation · easy

   After running df.groupby('region')['sales'].mean(), what does the result tell you?

   • AThe highest sales value for each region
   • BThe total sales for each region
   • CThe average sales for each region
   • DThe number of sales records for each region
   Reveal Solution Discussion Select an answer first
4. 23foundation · easy

   Which Pandas method is used to reorder the rows of a DataFrame based on the values in one or more columns?

   • Asort_values()
   • Bdrop()
   • Cfilter()
   • Dreindex()
   Reveal Solution Discussion Select an answer first
5. 24application · medium

   A NumPy array 'a' has shape (3,) with values [1, 2, 3]. Another array 'b' has shape (3, 1) with values [[10], [20], [30]]. An analyst computes 'a + b'. What is the shape of the result?

   • A(3,)
   • BAn error is raised
   • C(3, 3)
   • D(3, 1)
   Reveal Solution Discussion Select an answer first
6. 25expert · medium

   A NumPy array 'a' has shape (2, 3) with values [[1, 2, 3], [4, 5, 6]]. An analyst wants to compute the mean of each column. Which operation produces a 1-D array of column means?

   • Anp.mean(a, axis=1)
   • Ba.mean(axis=0)
   • Ca.mean(axis=1)
   • Da.mean()
   Reveal Solution Discussion Select an answer first