The price of one share of stock in the Pilsdorff Beer Company (see [[guide:Ee45340c30#sec 8.2 |Exercise.]]) is given by [math]Y_n[/math] on the [math]n[/math]th day of the year. Finn observes that the differences [math]X_n = Y_{n + 1} - Y_n[/math] appear to be independent random variables with a common distribution having mean [math]\mu = 0[/math] and variance [math]\sigma^2 = 1/4[/math]. If [math]Y_1 = 100[/math], estimate the probability that [math]Y_{365}[/math] is

• [math]{} \geq 100[/math].
• [math]{} \geq 110[/math].
• [math]{} \geq 120[/math].