Data Science Technology and Application [Chinese University MOOC]: Data Summary and Statistics (2)_Third Unit Test_Answer_Donghua University Data Science Technology Song Hui_HerbertHu’s Blog

class=”markdown_views prism-tomorrow-night”> Data Science Technology and Application Data summary and statistics (2) Answers to the third unit test Source of topic: Chinese University MOOC-Donghua University-Song Hui, etc.-Data Science Technology and Application 1 Single choice (1 point) There are 3 student information tables, stored as DataFrame objects stu1, stu2, stu3, with the same column index, the method of merging is ________. A.pd.concat( [stu1,sut2,sut3] ) B.[stu1,stu2,stu3].concat(axis =0) C.stu1. concat([sut2,sut3]) D.pd.concat(stu1,sut2,sut3) 2 single choice (1 point) The statistic “variance” describes ________. A. The most frequently occurring value in the sample B. The average value of the sample (a set of data) C. The degree of dispersion of the sample individual from the mean value D. The proportion of different values ​​​​in the sample to the sample size 3 Single choice (1 point) The method of counting the number of students in each ‘province’ in the DataFrame object stu is ________. A.stu[‘province’].value_counts() B.stu[‘province’].count() C.stu[].value_counts(‘province ‘) D.pd.value_counts(stu[‘province’]) 4 Single choice (1 point) Assuming that there are 12 columns in the DataFrame object temp, the statement ________ deletes rows with more than 3 null values ​​(NaN). A.temp.dropna(threshold = 9) B.temp.dropna(threshold