This value determines the maximum number of attempts a student is given to answer any of the questions in the lesson. In the case of questions which do not provide the answer, for example, Short Answer and Numerical questions, this value provides a necessary escape routine to the next page in the lesson.
Setting this value to 1 gives the students just one chance to answer each question.
Note that this value is global parameter and that it applies to all the questions in the lesson regardless of their type.
Note that this parameter does not apply to teachers.