All the question required manual calculation . NO internet and website .

1	If the area to the right is 81% for a Normal Distribution, what z-score should be used?
2	Based on the Central Limit Theorem, is it OK to use Normal distribution for the sample mean if the population is normally distributed and the sample size is 21.
3	What will be the impact on the standard deviation of the population if your sample size increases?
4	If the mean is 975 and std dev is 160, what is the cut-off for the bottom 10%? Assume normal distribution.
5	If the mean is 975 and std dev is 160, what is the cut-off for the bottom 10%? Assume t-distribution and a sample of size 26.
6	Non-sampling error can be reduced by increasing the sample size. True or False
7	According to Central Limit Theorem, if the population is Normal, then the sample mean distribution will be Normal only if the sample size is 30 or more. True or False
	Form a population where the known defectives are supposed to be 14%, you pick a sample of 145 parts. Answer the next 3 questions.
8	What is the standard error of the sampling proportion?
9	What is the probability that the population will have more that 17% defective parts?
10	What is the probability that between 12 and 17% part will be defective?
11	If the standard error of the sample mean is 4.5 and the sample size is 64, what is the population std dev?
12	The 16-oz bottles are actually filled with a machine setting of 16.4. The std dev of filling machine is rather high. It is 0.5 oz. You pick a sample of 6 bottles. What is the probability that the sample mean will be less than 16 oz?
13	For the above question, what is the probability that a bottle will weigh less than 16 oz?
14	For the above question, what is the probability that a bottle will weigh 16 oz?
15	True or False: As sample size decreases, T-distribution becomes like Z-distribution.