With reference to the S&P 500 index (ticker symbol is GSPC), obtain historical daily data for S&P 500 index based on its ticker symbol using yahoo finance and perform the following tasks (30 marks):

a. Perform the necessary calculations to analyze its volatility using the most recent 10 daily observations available.

b. Perform the necessary calculations to analyze its volatility using 10 daily observations in September 2008.

c. Conduct a relative comparison of the volatilities in 2 a) above and 2 b). Additionally, discuss the potential reasons for differences in volatilities. Cite necessary published journal papers to support your arguments.