Question

The distribution of ages of females in the United States is strongly skewed to the left with a mean of 80.2 years. A random sample of n 20 females is taken from this population and the mean age of the sample is calculated. This is repeated 500 times. Which one of the following best describes the shape of the sampling distribution? 20. Cannot be determined because the standard deviation is unknown. Skewed to the left with a mean of (A) (B) 80.2 (C) Skewed to the left with a mean of 80.2. (D) Approximately normally distributed with a mean of 80.2. 80.2 Approximately normally distributed with a mean of (E) A simple random sam 21. 23. Which of the following are resistant to ouliers? (A) The mean and standard deviation. (B) The median and standard deyiation (C) The median and the range. (D) The median and the IQR. (E) The range and IQR Consumers frequently complain that there is a large variation in prices charged by different pharmacies and drug stores for the same medication. A survey of a large sample of the 24. acies in a major city revealed that the prices charged for one bottle containing 50 tablets of a popular pain reliever were approximately normally distributed. The charge of S 10.48 for this bottle was at the 90th percentile and 20% ofthe bottles cost less than $8.61. What are, respectively, the approximate mean and standard deviation of the price distribution for bottles of this pain reliever? $9.35 and $0.88 $9.41 and $2.67 $9.55 and $0.31 $9.55 and $1.70 $9.73 and $1.87 (A) (B) (C) (D) (E) 25. An electronics company is testing whether a new assembly process will increase the number of circuits that can be produced daily by each worker. Nine people are randomly selected to participate in the study. They are trained in the new assembly process. When training is completed, the number of circuits that they produce in a day is recorded. The number of circuits assembled in one day using the new method was then compared to the number of circuits assembled in one day using the old method The results from both methods are shown in the following table 1 2 3 4 5 6 7 8 9 Old method (units per day) 67 New method (units per day) 68 73 77 6965 70 69 70 169 168 | 74 T77 | 72 168 171 172 71 The mull hypothesis H,: The training had no effect on the mean numberof cireuits that could be assembled daily was tested versus the altenate hypothesis H,: The training increased the mean number of circuits that could be assembled daily. Using the proper test statistic, which one of the following is the correct decision rule if-0.057 (A) (B) (C) (D) (E) Reject H, if the test statistic is greater than 1.645 Reject H, ifthe test statistic is greater than 1.812. Reject H, if the test statistic is greater than 1.833. Reject H, if the test statistic is greater than 1.860. Reject H, if the test statistic is greater than 2.262.

Answer 1

20) option D is correct

23) option D is correct

24) option A is correct

25)option D is correct