Roth IRA doesn't get you a tax deduction for the contributions, but the earnings grow tax free and you don't pay tax on the withdrawals after retirement. A traditional IRA gives you a tax deduction for the contributions at the time you make them, and the earnings grow tax free, but when you withdraw the money after retirement, you are taxed on it. The idea is that you are hopefully in a lower tax bracket at that point. So its only natural that Roth IRA is the best.
Negative correlation describes a relationship of two variables in which one variable increases while the other decreases. It shows the the level at which the variables moves in opposite directions to each other.
In the given example, the two variables are inversely proportional. On plotting the variables against each other, it would have a downward slope. The correlation coefficient, r = -0.94, shows that the number of tardies of a student, x, and grade point average (GPA), y, have a linear relationship. As correlation coefficient is a measure of linear relationship, which could be negative, zero, or positive.
Since 6n and 3n have the same variables you need to subtract them. So 6n-3n=3n. Now you have 3n=15. To get n by it’s self you need to divide 3 by 15. 3 divided by 15 is 5. This means that n=5. Hope this helps!!