A firm's total investment in an investment fund is $2 million. The amount invested in Stocks A, B, C, and D are $200,000, $300,000, $500,000, and $1,000,000 respectively. The betas of the Stocks A, B, C, and D are 1.50, 0.50, 1.25, and 0.75 respectively. Calculate the beta of the investment fund.