(b) A secondary school in a town consists of 1500 students. Of these, 734 students own a personal computer at home. A random sample of 150 students was selected from this school. (i) What is the standard deviation of the sample proportion having own a personal computer at home? (1i) What is the probability that the sample proportion is more than 0.5? (c) Find the probability that a random sample of 25 observations, from a normal population with variance o' =6 , will have a sample variance greater than 9.1