hep me solve this please

IIL. Solve the following problems in separate sheets of paper. 21. The amount of pyridoxine (in grams) per multiple vitamin is normally distributed with =110 grams and s=25 grams. A sample of 25 vitamins is to be selected. (1) What is the probability that the sample mean will be between 100 and 120 grams? (2) What is the probability that the sample mean will be less than 100 grams? (3) What is the probability that the sample mean will be greater than 100 grams? (4) 95% of all sample means will be greater than how many grams? 22. The amount of time required for an oil and filter change on an automobile is normally distributed with a mean of 45 minutes and a standard deviation of 10 minutes. A random sample of 16 cars is selected. (1) What would you expect the standard error of the mean to be? (2) What is the probability that the sample mean is between 45 and 52 minutes? (3) What is the probability that the sample mean will be between 39 and 48 minutes? (4) 90% of the sample means will be greater than what value? 23. The amount of bleach a machine pours into bottles has a mean of 36oz. with a standard deviation of 0.15oz. Suppose we take a random sample of 36 bottles filled by this machine. (1) What is the probability that the mean of the sample exceeds 36.01 oz? (2) What is the probability that the mean of the sample is less than 36.03 ? (3) What is the probability that the mean of the sample is between 35.94 and 36.06oz ? (4) What is the probability that the mean of the sample is between 35.95 and 35.98 oz? 24. A manufacturer of power tools claims that the average amount of time required to assemble their top-of-the-line table saw is 80 minutes with a standard deviation of 40 minutes. Suppose a random sample of 64 purchasers of this table saw is taken. (1) What is the mean of the sampling distribution of the sample mcan (2) What is the standard deviation of the sampling distribution of the sample mean? (3) What is the probability that the sample mean will be less than 82 minutes? (4) What is the probability that the sample mean will be between 77 and 89 minutes? (5) What is the probability that the sample mean will be greater than 88 minutes? 25. According to a survey, only 15% of customers who visited the web site of a major retail store made a purchase. Random samples of size 50 are selected. (1) What is the average of all the sample proportions of customers who will make a purchase after visiting the web site? (2) What is the standard deviation of all the sample proportions of customers who will make a purchase after visiting the web site? (3) What proportion of the samples will have between 20% and 30% of customers who will make a purchase after visiting the web site? (4) What proportion of the samples will have less than 15% of customers who will make a purchase after visiting the web site? (5) What is the probability that a random sample of 50 will have at least 30% of customers who will make a purchase after visiting the web site? (6) 90% of the samples will have less than what percentage of customers who will make a purchase after visiting the web site? (7) 90% of the samples will have more than what percentage of customers who will make a purchase after visiting the web site