Questions: In a gradebook table, students who did not take Test1 have a null value in the Test1 column. When you calculate the class average for Test1, you want to replace those null values with 0 so that the null values will be included in the calculation. Which of these statements will convert those null values to 0 and find the average? a) AVG(Coalesce(Test1, 0)) FROM gradebooks b) SELECT AVG(COALESCE(Test1, 0)) FROM gradebook; c) SELECT Coalesce(Test1, 0)) FROM gradebook; d) SELECT AVG(Test1, 0) FROM gradebook;

The answer is the second one (b):

sql SELECT AVG(COALESCE(Test1, 0)) FROM gradebook;

Explanation for each option:

a) `AVG(Coalesce(Test1, 0)) FROM gradebooks`: This option is incorrect because it lacks the `SELECT` keyword, which is necessary to form a complete SQL query. Additionally, the table name should be `gradebook` instead of `gradebooks`.

b) `SELECT AVG(COALESCE(Test1, 0)) FROM gradebook;`: This option is correct. It uses the `COALESCE` function to replace `NULL` values in the `Test1` column with `0` and then calculates the average of the resulting values. The syntax is correct, and it includes the necessary `SELECT` keyword.

c) `SELECT CoAlesce(Test1, 0)) FROM gradebook;`: This option is incorrect because it attempts to use the `COALESCE` function without applying an aggregate function like `AVG`. It also has a syntax error with an extra closing parenthesis.

d) `SELECT AVG(Test1, 0) FROM gradebook;`: This option is incorrect because the `AVG` function does not accept two arguments. The `COALESCE` function should be used to handle `NULL` values before applying the `AVG` function.

In summary, option (b) correctly uses the `COALESCE` function to replace `NULL` values with `0` and calculates the average of the `Test1` column.