part a: The times for a particular journey during rush hour in a large city have to mean 24.4 minutes and standard deviation 9.9 minutes. Using the Central limit theorem: Find the probability that the mean time taken for a random sample of 70 of the time for this journey is more than 25 minutes.
part b:
The weights, in grams, of bags of cocoa beans, are known to have a standard deviation of 4 grams. A random sample of bags is weighted with the following results:
746, 748, 754, 752, 747, 756, 751, 740, 759, 755
Calculate a 96% confidence interval for the mean weight of a bag of cocoa beans
part c:
A factory produces a particular electrical component and on average 0.97 is correctly. In a batch of 120 components taken at random, using the Binomial probability distribution, what is the probability that exactly 2 components are faulty?