Which experimental study design eliminates the impact of the testing effect by leaving out the pretest?

Researchers find that people who watched a movie about a flu outbreak washed their hands more often, but the handwashing data were collected before the movie was released. Which criterion for inferring causality was not met?

A researcher uses a tape measure to calculate store space allotted to tobacco products, and after the 25th store the tape measure becomes stretched out. Which threat to internal validity does this describe?

How many rows will be returned by the following query? SELECT name FROM student WHERE major BETWEEN ‘Data Science’ AND ‘Computer Science’;

Questions 16 to 18: Primary Keys & Normalization Concepts   Question 18 You have a Phone_Numbers column that contains values like “123-456-7890, 987-654-3210”. Under what condition does this violate 1NF?

How many rows will be returned by the following query? SELECT name FROM student WHERE major LIKE ‘%o%’;

Questions 7 to 9: String Functions on Database Rows   Question 9 What will the following command return? SELECT SUBSTRING_INDEX(name, ‘ ‘, -1) AS ‘Last_Name’ FROM student WHERE id = 101;

Questions 10 to 15: Standalone String Functions   Question 12 What will the following command return? SELECT SUBSTRING(‘192.168.1.100’, 5, 3);

Questions 10 to 15: Standalone String Functions   Question 13 What will the following command return? SELECT SUBSTRING(SUBSTRING_INDEX(‘apple-banana-cherry’, ‘-‘, -2), 1, 6);

Questions 19 to 20: Evaluating 1NF Compliance   Question 20 Below is a table description and its data: mysql> DESC projects; +———+————–+——+—–+———+—————-+ | Field | Type | Null | Key | Default | Extra | +———+————–+——+—–+———+—————-+ | id      | int     | NO  | PRI | NULL    | auto_increment | | title  | varchar(50) | YES |   | NULL |   | | members | varchar(100) | YES | | NULL | | +———+————–+——+—–+———+—————-+   mysql> SELECT* FROM projects; +—-+——————+_______________+ | id | title | members | +—-+——————+_______________+ | 1 | Mobile App | Alice, Bob, Charlie | | 2 | AI Chatbot | Diana, Evan | +—-+——————+_______________+ Is the above table in First Normal Form (1NF)?