QUESTION 1 Which of the following are true? Cl The probability of making a Type I error is conditional on the Null Hypothesis being true. Cl AType || error cannot occur if the decision is do not reject the null hypothesis Cl Type | and Type II errors can occur together. D The decision rule is usually formulated so that there is a low probability of making a Type I error QUESTION 2 Awholesaler buys pre-packed sugar in bags with an advertised mean weight of 5 kgs. He wishes to conduct a hypothesis test to check the validity of the advertised weight. Which of the following alternative hypotheses is appropriate? O Ha: u= 5 kg (equal to) 0 Ha: p, s 5 kg (less than or equal to) O Ha: pt 5 kg (not equal to) O Ha: u> 5 kg (greater than) QUESTION 3 A random sample of 74 was drawn from a large normal population, and the mean and standard deviation were found to be 32.5 and 2.78. The analyst wishes to test at the 5% level of significance whether the population mean is over 32. 1. Use the tables in the textbook to determine the critical value for the test statistic. State your answer correct to three decimal places. 2. Does the evidence support the hypothesis that the population mean is over 32? (yes or no) QUESTION 4 2 points Save! Consider the following statements concerning the methodology of classical hypothesis testing: A. The decision to reject the null hypothesis is made when the p-value is less than alpha. B. The decision to reject Ho implies that the sample data used for the test must have been inappropriate and a different sample will always need to be reselected. C. When the level of significance is decreased for a test where Ha specifies that the value of the population parameter has decreased, then the critical value for the test also decreases. O onIyA is true O onIyAand B are true O onIyAand C are true O only B and C are true 0 all three statements are true Question Completion Status: QUESTION 5 5 pain The manager ofTile Central believes that the Virginia store is more protable, in terms of weekly profit per full-time employee, than the store at Clayfield. Random samples of 13 and 'IS accounting records for Clayfield and Virginia, respectively, were taken. These yielded average weekly profit per full-time employees for Clayfield and Virginia of $288.13 and $310.05, respectively, and variances of 889.52 $ squared and 1057.28 $ squared. It is assumed that the population variances are the same and the distribution of weekly profit per full time employee for both stores approximates a normal distribution. Assume alpha = 0.05. 'I. If the hypotheses are to be written as Clayfield minus Virginia, what is the direction of the alternative hypothesis? Type the letters gt (greater than), ge (greater than or equal to), It (less than), le (less than or equal to) or ne (not equal to) as appropriate in the box. 2. Determine the standard error for the difference between means, reporting your answer to three decimal places. 3. Calculate the test statistic, reporting your answer to two decimal places. 4. Is the null hypothesis rejected for this test? Type yes or no. 5. Regardless of your answer for 4, if the null hypothesis was rejected, can we conclude that the manager's claim is valid at the 5% level of significance? Type yes or no. QUESTION 6 2 points Save Answer A university administrator believes that less than 40% of fulltime staff regularly use public transport to travel to the university. In a survey of 50 full-time staff. only 14 indicated that they regularly use public transport. On the basis of this evidence, the administrator would O not reject the null hypothesis at the 5% level but reject it at the 1% level. O reject the null hypothesis at the 5% level but not at the 1% level. O reject the null hypothesis at both the 5% and 1% levels. 0 not reject the null hypothesis at both the 5% and 1% levels. QUESTION 7 : nninl-e (nun Anclunr QUESTION 8 The Australian Medical Association believed that the Health Minister's recent statement claiming that 70% of doctors supported the reforms to Medicare was incorrect. It thought that the actual support for the reforms was lower than this. The Association's President suggested the best way to test this was to survey 225 members, selected through a random sample, on the issue. She indicated that the Association would be prepared to accept a Type I error probability of 0.05. 1. State the direction of the alternative hypothesis for the test.Type gt (greater than), ge (greater than or equal to), It (less than), le (less than or equal to) or ne (not equal to) as appropriate in the box. 2. State, in absolute terms, the critical value as found in the tables in the textbook. 3. Determine the lower boundary of the region of non-rejection in terms of the sampl_emportion of respondents (as a % to two decimal places) in favour of the reforms. If there is no (theoretical) lower boundary, type It in the box. 4. Determine the upper boundary of the region of non-rejection in terms of the sampl_emportion of respondents (as a % to two decimal places) in favour of the reforms. If there is no (theoretical) upper boundary, type gt in the box. 5. If 144 of the survey participants indicated support for the reforms, is the null hypothesis rejected for this test? Type yes or no. 6. Disregarding your answer for 5, if the null hypothesis was rejected, could the Association claim that the Health Minister's assertion is incorrect at the 5% level of significance? 6 poin1 Question Completion Status: QUESTION 9 Suppose that the duration of trouble-free operation of a new vacuum cleaner is normally distributed with mean 500 days and a standard deviation of 81 days. The research department randomly selects 36 customers who bought these vacuum cleaners and records duration (in days) of trouble- free operation. The standard error of the sample mean is days (1 decimal place). The probability that the average duration of trouble-free operation time is between 480 days and 530 days is (4 decimal places). QUESTION 10 1 point Consider the following descriptive statistics from Excel for a sample of bread loaf weights (in grams) baked in a Brisbane bakery. Median 451 Standard Deviation 210.7663 Range 785 Minimum 264 Maximum 1049 Sum 6155 Count 13 What is the 95% confidence interval for the population mean weight of a bread loaf baked in this bakery? O a. 438.14