Good day,

I hope you are doing well :)

I am struggling with the concepts of significance levels and null and alternative hypothesis as well as critical values.

I would like some assistance and an explanation on the following specific questions individually.

Please note that I would like for these specific questions to be explained.

Your assistance would be greatly appreciated.

I look forward to your reply.

Kind regards.

Question 1 10 points Save Answer A telephone company's records indicate that private customers pay on average R17.10 per month for long distance calls. A random sample of 10 customers' accounts during the given month produced a sample mean of R22.10 expended for long distance calls and a sample variance of R45. A 5% significance test is to respectively. be performed to determine if the mean level of billing for long distance calls per month is more than R17.10. The null and alternative hypothesis are O HO: H = 17.10 ; Ha: H 22.10 O HO: H = 17.10 ; Ha: H > 17.10 O HO: H = 17.10 ; Ha: H # 17.10 O HO: W = 22.10 ; Ha: H * 22.10 Question 2 10 points Save Answer A pharmaceutical company claims that a certain drug causes 80% of people to recover from a disease. Out of 200 people who were given this drug, 153 recovered. For the test of the company's claim for a = 0.05, do we reject H o and what is the critical value: Yes, #1.645 O No, #1.645 Yes, +1.96 O No, #1.96 Yes, +1.28 Question 3 10 points Suppose that we want to test if a machine puts 50kg of mielies into bags on average. We take a sample of 40 bags and find that the average amount of mie each bag is 48.9kg with a standard deviation of 1.1kg. For the test of the hypothesis H o: u = 50 versus H a: H # 50 using a 5% significance level, what is the t statistic? O 5.7496 O -5.7496 6.3246 O -6.3246 -36.3636 Question 4 10 points Save Answer Suppose we have a random sample of size 40, with a standard deviation of 9.45, from a normal population. We want to test Ho: o 2 = 100 versus Ha: 0 2 # 100. What is the test statistic? 36.8550 34.8280 3.6855 35.7210 348.2798 Question 5 10 points Save Ans A random sample of 150 women shows that 45 are against certain new working hours. A newspaper claims that less than 33% of women are against the new working hours. Test the claim at 0,1 level of significance. Determine the critical value. 2.326 O 1.895 O - 1.282 O - 2.326 Question 6 10 points Save Answer Suppose we have a random sample of size 30, with a standard deviation of 9.45, from a normal population. We want to test H o: o 2 = 100 versus Ha: 0 2 = 100. For a = 0.05, what is the critical values? O 18.49 and 43.77 17.71 and 42.56 16.05 and 45.72 16.79 and 46.98 1.699 and 2.045 Question 7 10 points Save Answer The policy of a particular bank branch is that the ATM must be stocked with enough cash to satisfy customers making withdrawals over an entire weekend. At this branch, the average amount of money withdrawn from the ATM machines per customer transaction over the weekend is R240 with the standard deviation of R40. Suppose that a random sample of 36 customer transactions was examined and it is observed that the sample mean withdrawal is R258. Suppose we test at the 5% level of significance whether there is reason to believe that the true mean withdrawal is greater than R240. Determine the critical value. 3.090 O 2.326 O 1.96 O 2.030 O 1.645 Question 8 10 points Save Answer According to "Dietary Goals for the United States (1997)", high sodium intake may be related to ulcers, stomach cancer, and migraine headaches. The human requirement for salt is only 220 milligram per day, which is surpassed in most single servings of ready-to-eat cereals. If a random sample of 20 similar servings of Special K has a mean sodium content of 244 milligrams and a standard deviation 24,5 milligrams does this suggest at 0,01 level of significance that the average sodium content for single servings of Special K is less than 220 milligrams? Assume the distribution of sodium content to be normal. Determine the critical value. O 2.528 O 1.328 2.528 O -2.539 O -2.528