#Grading Exercise
Instructions: Fork and clone this repository. Create a file called grader.js and write the following functions inside of it. You must have full test coverage (write a bunch of jasmine or mocha/chai tests for each function). This is an open-book exercise. Feel free to refer to your notes and the jasmine or mocha/chai docs.
###Letter Grader
Write a function letterGrader which takes a test score and returns the equivalent letter grade.
- A: 90-100
- B: 80-89
- C: 70-79
- D: 60-69
- F: 0-59
letterGrader(98);
//=> 'A'
Bonus: Add '+' and '-' grades. So a 98 is actually a A+ and an 80 is a B-
###Average
Write a function 'averageScore` which takes an array of test scores and returns the average score.
averageScore([90, 95, 87, 60]);
//=> 83
###Median
Write a function medianScore which takes an array of test scores and calculates the median score. The median is the middle value. If there are an even number of scores, calculate the average of the middle two scores.
medianScore([52,80,80,86,94])
//=> 80
###Mode
Write a function modeScore which takes an array of test scores and calculates the mode score. The mode is the value that appears most often.
modeScore([82, 92, 75, 91, 92, 89, 95, 100, 86])
//=> 92