A bond investor has gathered the following information on a 10-year, semi-annual pay US corporate bond: Currently trading at par value Annual coupon of 10% Estimated price if rates increases by 50bps is 96.99% Estimated price if rates decreases by 50bps is 103.14% a) What is the effective duration? Will the estimate of the increase in an option-free bond's price, based only on its duration be too small, too large, or not enough information to determine and why