Question 1: A supermarket chain believes that customers to its stores spend half-an-hour or more, on average, doing their purchases. A consumer body wants to verify this claim. it observed the entry and departure times of 86 randomly selected customers from supermarkets in the chain. The sample average time in the store was 29minutes. Assume a population standard deviation of 9 minutes and that shopping time is approximately normally distributed. Calculate the value of the statistic. A. -1.03 B. -1.855 C. 1.96 D. -2.33 E. 30 minutes

Question 2: Determine a 99% confidence interval for the true proportion of all employees of ABC Ltd who believe that they should be given a raise by the company, given that 120 out of a sample of 200 employees support this suggestion. A. 0.5321 0.6679 B. 0.5557 0.6443 C. 0.5193 0.6807 D. 0.5108 0.6892 E. 0.543 0.6570

Question 3: A motor vehicle insurance advisor stated recently in a newspaper report that more than 60% of Johannesburg motorists do not have motor vehicle insurance. A random survey amongst 100 motorists found that 60 do not have motor vehicle insurance. A random survey amongst 100 motorists found that 60 do not have motor vehicle insurance. Compute the p-value of the statistic. A. 0.36 B. 0.5 C. 1.00 D. Approximately zero E. 0.60

Question 4: Determine a 95% confidence interval for the true average monthly salary earned by all employees of ABC Ltd, if it was found that the average monthly salary earned by a sample of 19 employees of the company was R18500, with a standard deviation of R1750. A. R17803.84 R19196.16 B. R17656.50 R19343.50 C. R17839.57 R19160.43 D. R17344.39 R19655.61 E. R17465.79 R19534.21

Question 5: The average time taken by a sample of 68 runners to complete a 10km race was 43 minutes. Assuming a population standard deviation of 8.65minutes, determine a 90% confidence interval for the true average time taken by all runners to complete the race. A. 39.30 44.70 B. 39.56 44.44 C. 39.94 44.06 D. 40.27 43.73 E. 33.75 50.25

Question 6: Previous experience has indicated that, on average, customers of a local pet food store spend R550 per purchase, with a standard deviation of R75. A sample of 105 purchases is randomly selected. Assuming a normal distribution, determine the standard error for this sample. A. 7.3193 B. 768.52 C. 5 D. 75 E. 0.7319

Question 7: Previous experience has indicated that, on average, customers of a local pet food store spend R550 per purchase, with standard deviation of R75. A sample of 105 purchases is randomly selected. assuming a normal distribution, what is the probability that the mean value of the purchases in the sample is less than R555? A. 0.6831 B. 0.3169 C. 0.2482 D. 0.2857 E. 0.7518

Question 8: The ABC Bowling club has found that 45% of its members attended school in the pretoria area. A sample of 135 members is randomly selected from the area. Assuming a normal distribution, what is the probability that more than 46.50% of the members of the club in the sample attended school in Pretoria? A. 0.3632 B. 0.6368 C. 0.4500 D. 0.3500 E. 0.4620

Question 9: The ABC Bowling club has found that 45% of its members attended school in the pretoria area. A sample of 135 members is randomly selected from the area. Assuming a normal distribution, determine the standard error for this sample. A. 0.0428 B. 0.0018 C. 0.45 D. 0.55 E. 0.2475

Question 10: In a sample size of 16 selected from a normal population, x=52 and s=5. If you are testing the null hypothesis H0 : 50, at the 10% level of significance, what is the decision rule for accepting or rejecting H0? A. Reject H0 if zstat > 1.96 B. Reject H0 if zstat < -1.645 C. Reject H0 if tstat < -1.3406 D. Reject H0 if tstat > 2.576 E. Reject H0 if tstat < -1.28