The length of time (in years) until a particular radioactive particle decays is a random variable t with the probability density function by: f(t) = 0.03e^(-0.03t); for t in [0, infinity]find the mean of the distribution, the standard deviation of the distribution, and the probability that the random variable is between the mean and one standard deviation above the mean

Astudy was interested in determining if eating milk chocolate lowered someone's cholesterol levels.ten people's cholesterol was measured. then, each of these individuals were told to eat 100g of milk chocolate every day and to eat as they normally did. after two weeks, their cholesterol levels were measured again. is there evidence to support that their cholesterol levels went down? how should we write the alternative hypothesis? (mud = the population mean difference= before - after)a. ha: mud = 0b. ha: mud > 0c. ha: mud < 0d. ha: mud does not equal 0