Complete the problems:
1. The statistics of the grades of a test are: P15 = 40, P55 = 62, P75 = 81. What percentage of the students had a mark that is:
a) more than 40?
b) between 40 and 81?
2. Ann's grade for her physics test is 73%; the class results for the physics test have a mean of 60% and a standard deviation of 3. Ann's grade for her biology test is 69%; the class resudlts for the biology test have a mean of 51% and a standard deviation of 2. Which test result has the higher relative position for Ann?
3. The scores for a test have a normal distribution with a mean of 60 and a standard deviation of 5.
a) Approximately what percentage of the scores is between 50 and 70?
b) Approximately what percentage of the scores is less than 55?
Attachment:- Objectives.rar