Exercise 1: Write the following methods in a Java project: a) A Java method to determine and return the result of factorial for a number received as a parameter. b) A Java method to determine and print the location(s) of the word in a file, where the filename and word are received as parameters. c) A Java method to determine and return the average of integers in an array. The method receives the array of integers as a parameter, and then it returns the average (mean). d) A Java method to determine and return the standard deviation of integers in an array. The method receives the array of integers as a parameter, and then it returns the standard deviation (hint: you may use the method created in step (c)). 120 (0; -22 N -1 8 sample standard deviation N the number of observations is the observed values of a sample item the mean value of the observations e) Test the above methods from the main method