CDA level1 multi topic selection

1. Table structure is a commonly used data structure in data analysis , The following belongs to the table structure analysis tool
• A.DB2
• B.Power BI
• C.Excel
• D.PPT
answer .ABC. D Options PPT It belongs to office software

2. The integrity of data indicates ： The state that all data values stored in the database are correct , stay SQL Of CREATE TABLE Statements that implement integrity constraints include （）
• A.NOT NULL
• B.PRIMARY KEY
• C.DEFAULT
• D.UNIQUE
answer ：ABD. In order to ensure the integrity of the data , It can be achieved in four ways , constraint 、 The rules 、 The default value is 、 trigger . The title stem says yes “ stay CREATE TABLE Statements that implement integrity constraints include ”, So we can only choose from restrictive conditions Integrity constraints include ： Primary key constraint （PRIMARY KEY）、 Foreign key constraints （FOREIGN KEY）、 Unique constraint （UNIQUE）、 Non empty constraint （NOT NULL）、 Check constraint （CHECK）. So don't choose C

3. If you want to analyze the correlation between categorical variables , Which of the following methods can be used （ ）
• A. Chi square test
• B.t test
• C. Calculate the Pearson correlation coefficient
• D. Calculate the correlation coefficient (coefficient of contingency)
answer ：AD.BC It can only be used to analyze numerical variables , Categorizing variables does not use these two methods .

4. The fact table is a table used to record the results of business behavior , The following is a table of facts
• A. The order sheet
• B. Order details sheet
• C. Customer list
• D. Product list
answer ：AB.A、B The option is the record data sheet about consumption behavior and details of consumption behavior , It belongs to the fact table ,C、D It is the dimensional information of observing consumption behavior , Book friend dimension table , So the correct answer is A、B two

5. stay “ People and goods yard ” Under the business module , It may become a description “ site ” The relevant data sheet of the situation is
• A. The order sheet
• B. Order details sheet
• C. Customer details table
• D. Area table
answer ：AB.“ People and goods yard ” Medium “ site ” It refers to the business modules related to transaction behavior , therefore AB It's the right choice