chap9-rev-f07.rtf

chap9-rev-f07.rtf - MA 116-Chapter 9 Review Name In a word...

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MA 116 - Chapter 9 Review Name___________________________________ In a word problem, first identify if you are dealing with one or two populations, with means or proportions, with constructing a confidence interval, finding the sample size or testing a hypothesis. In problems about constructing confidence intervals or testing hypothesis for one population you are supposed to solve with the formula, and then check with a feature of the calculator. In problems about two populations, solve with a feature of the calculator; we did not learn the formulas in class. Always list the statistics provided in the problem, and indicate the feature used and the results obtained. Answers to confidence intervals should be written with one of the two notations used in the book. Practice both please. Remember to define the population(s), and the variable or the success attribute (if you are dealing with proportions). MATH 116 – FALL 2011 – FOR EXAM 3 YOU CAN PRACTICE SOLVING PROBLEMS 1-16, 20, 23 For problems 1 and 2, a hypothesis test is to be performed for a population mean with null hypothesis : μ = . Find the required critical value(s) and describe the decision criterion based on the critical value approach. 1) α = 0.08 for a two - tailed test. 2) α = 0.02 for a left - tailed test. A one - sample z - test for a population mean is to be performed. Determine the 3) A right - tailed test: z = 2.38 4) A left - tailed test: z = - 2.65 5) A two - tailed test: z = 1.31 6) When performing a one - sample z - test for a population mean, what criterion do you use for rejecting the null hypothesis using the critical value approach? Using the approach? Assume that a test is being performed. 7) A population is normally distributed with a standard deviation . We wish to test the hypotheses . 1

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A 177 - item sample has a mean = 25,436.1. Compute the value of the test statistic. 8) Jenny is conducting a hypothesis test concerning a population mean. The hypotheses are as follows. : μ = 50 : μ > 50 She selects a sample and finds that the sample mean is 54.2. She then does some calculations and is able to make the following statement: If were true, the chance that the sample mean would have come out as big ( or bigger) than 54.2 is 0.3. Do you think that she should reject the null hypothesis? Why or why not? 9) Suppose that you wish to perform a hypothesis test for a population mean. Suppose that the population standard deviation is unknown, the population is skewed to the right, and the sample is large. Would you perform a or a Why? Would the test be exact or approximate? 10) Suppose that you wish to perform a hypothesis test for a population mean. Suppose that the population standard deviation is unknown, the population is normally distributed, and the sample size is small. Would you perform a or a Why? Would the test be exact or approximate? 11) A one - sample z - test for a population mean is to be performed. Let denote the observed value of the test statistic, z. True or false, for a test, the is the area under the standard normal curve to the left of ?
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