STATISTICS AND PROBABILITY FOR GRADE 11

I. Solve the following problems using the steps in hypothesis testing about population mean.

1. The mean waiting time for the processing of a personal loan in a certain bank is 90 minutes with a standard deviation of 25 minutes. The bank personnel are testing a new kind of processing method. If a random sample of 15 clients recorded a mean processing time of 78 minutes with standard deviation of 12 minutes using the new method, test the claim that the population mean is now less than 90 minutes. Use a 0.05 level of significance and assume that the population to be approximately normal.

2. The manufacturer of a particular brand of canned tuna claims that each can has an average weight of 150 grams with standard deviation of 8 grams. Suppose a random sample of 80 cans is tested and found to have an average weight of 145 grams, test the hypothesis that = 150 grams against the alternative hypothesis ? 150 grams with a 0.01 level of significance.

II. Solve the following problems using the steps in hypothesis testing about population proportion.

1. A television channel claims that 40% of the population who watch TV patronized their TV channel. After collecting 70 samples, they found that 30 of them watch the said TV channel. Use 0.01 level of significance to test their claim.

2. A medical technologist claims that 25% of the chain-smokers are teenagers. After making a survey of 42 chain-smokers, he found that 8 of them are teenagers. Using 95% confidence level, test whether his claim is supported or not.

I. Solve the following problems using the steps in hypothesis testing about population mean. 1. The mean waiting time for the processing of a personal loan in a certain bank is 90 minutes with a standard deviation of 25 minutes. The bank personnel are testing a new kind of processing method. If a random sample of 15 clients recorded a mean processing time of 78 minutes with standard deviation of 12 minutes using the new method, test the claim that the population mean is now less than 90 minutes. Use a 0.05 level of significance and assume that the population to be approximately normal. 2. The manufacturer of a particular brand of canned tuna claims that each can has an average weight of 150 grams with standard deviation of 8 grams. Suppose a random sample of 80 cans is tested and found to have an average weight of 145 grams, test the hypothesis that u = 150 grams against the alternative hypothesis u # 150 grams with a 0.01 level of significance. I. Solve the following problems using the steps in hypothesis testing about population proportion. 1. A television channel claims that 40% of the population who watch TV patronized their TV channel. After collecting 70 samples, they found that 30 of them watch the said TV channel. Use 0.01 level of significance to test their claim. 2. A medical technologist claims that 25% of the chain-smokers are teenagers. After making a survey of 42 chain-smokers, he found that 8 of them are teenagers. Using 95% confidence level, test whether his claim is supported or not