I need help understanding how to do this. What's the mean annual return of the S&P 400 Midcap Index over the past 7 years? What's the standard deviation? What's the mean annual return of the...

I need help understanding how to do this.

What's the mean annual return of the S&P 400 Midcap Index over the past 7 years? What's the standard deviation? What's the mean annual return of the NASDAQ-100 Index over the past 7 years? Calculate a coefficient of correlation of the two indexes' return. Explain what may be causing the changes in the indexes' return over the past 7 years.