FeCl₃ has a van't Hoff factor of 3.4. What is the freezing point (in °C) of an aqueous solution made with 0.81 m FeCl₃? (Kf for water is 1.86 °C/m)

Listed below are the amounts of mercury (in parts per million, or ppm) found in tuna sushi sampled at different stores. the sample mean is 0.836 ppm and the sample standard deviation is 0.253 ppm. use technology to construct a 90% confidence interval estimate of the mean amount of mercury in the population.