Consider the situation where x = accelerated strength of concrete and y = 28-day cured strength. suppose the simple linear regression model is valid for x between 1000 and 4000 and that beta_1 = 1.25 and sigma = 350. consider an experiment in which n = 7, and the x values at which observations are made are x_1 = 800, x_2 = 1300, x_3 = 1800, x_4 = 2300, x_5 = 2900, x_6 = 3700, and x_7 = 4100. calculate sigma_beta 1, the standard deviation of beta_1 (round your answer to four decimal places.) what is the probability that the estimated slope based on such observations will be between 1.00 and 1.50? (round your answer to four decimal places.)