Requesting a bit of help with my assignment - Pretty basic...

Question

I have an assignment where I have to create "public double findAverage()" and use if statements to determine the average based on different equations would be. I'll post it down in the thread. I feel confident I have that one properly done. Then I have to create "public char findLetterGrade()" and use if statements to determine the letter grade based on that average from the first one. When I compile it, the compiler highlights "if(average >= 90)" and says it cannot find symbol - variable average. Here's my full code, any help would be very much appreciated.
public class CompSciStudent
    private String name;
    private String year;
    private int labGrade;
    private int examGrade;
    public CompSciStudent(String inName, String inYear, int inLabGrade, int inExamGrade)
        name = inName;
        year = inYear;
        labGrade = inLabGrade;
        examGrade = inExamGrade;
    public CompSciStudent(String inName, String inYear)
        name = inName;
        year = inYear;
    public void setName(String inName)
        name = inName;
    public void setYear(String inYear)
        year = inYear;
    public void setLabGrade(int inLabGrade)
        labGrade = inLabGrade;
    public void setExamGrade(int inExamGrade)
        examGrade = inExamGrade;
    public String getName()
        return name;
    public String getYear()
        return year;
    public int getLabGrade()
        return labGrade;
    public int getExamGrade()
        return examGrade;
    public double findAverage()
        double average;
        if (year == "Fr")
            average = 0.70*examGrade + 0.30*labGrade;
        else if (year == "So")
            average = 0.65*examGrade + 0.35*labGrade;
        else if (year == "Jr")
            average = 0.60*examGrade + 0.40*labGrade;
        else if (year == "Sr")
            average = 0.50*examGrade + 0.50*labGrade;
        else
            average = 0.00;
         return average;
    public char findLetterGrade()
        char letterGrade;
        if (average >= 90)
            letterGrade = 'A';
        else if (90 > average >= 80)
            letterGrade = 'B';
        else if (80 > average >= 70)
            letterGrade = 'C';
        else if (70 > average >= 55)
            letterGrade = 'D';
        else if (average < 55)
            letterGrade = 'F';
        else
            letterGrade = 'E';
        return letterGrade;
}

Answer 1

public class CompSciStudent
    private String name;
    private String year;
    private int labGrade;
    private int examGrade;
    public CompSciStudent(String inName, String inYear, int inLabGrade, int inExamGrade)
        name = inName;
        year = inYear;
        labGrade = inLabGrade;
        examGrade = inExamGrade;
    public CompSciStudent(String inName, String inYear)
        name = inName;
        year = inYear;
    public void setName(String inName)
        name = inName;
    public void setYear(String inYear)
        year = inYear;
    public void setLabGrade(int inLabGrade)
        labGrade = inLabGrade;
    public void setExamGrade(int inExamGrade)
        examGrade = inExamGrade;
    public String getName()
        return name;
    public String getYear()
        return year;
    public int getLabGrade()
        return labGrade;
    public int getExamGrade()
        return examGrade;
    public double findAverage()
        double average=0.0; //change
        if (year == "Fr")
            average = 0.70*examGrade + 0.30*labGrade;
        else if (year == "So")
            average = 0.65*examGrade + 0.35*labGrade;
        else if (year == "Jr")
            average = 0.60*examGrade + 0.40*labGrade;
        else if (year == "Sr")
            average = 0.50*examGrade + 0.50*labGrade;
        else
            average = 0.00;
         return average;
    public char findLetterGrade()
        char letterGrade= 'A'; //change
        if (average >= 90)
            letterGrade = 'A';
        else if (90 > average >= 80)
            letterGrade = 'B';
        else if (80 > average >= 70)
            letterGrade = 'C';
        else if (70 > average >= 55)
            letterGrade = 'D';
        else if (average < 55)
            letterGrade = 'F';
        else
            letterGrade = 'E';
        return letterGrade;
}The Java Compiler has an issue when you send a variable into an if statement that hasn't been properly initialized (AKA with a value). This should work though.