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Unformatted text preview: • This is a long chapter, and it one of the two most important chapters in the book for you to understand. • The due date for this homework is February 7 th . • See Blackboard for assignment. Chapter 9: Homework • You should be able to recall: – The symbols used for the probabilities of Type 1 and Type 2 errors – What information is needed to calculate power before and after data is collected – When a Type 1 and when a Type 2 error can occur • You should be able to accomplish: – Test hypotheses on the mean of a normal distribution – Test hypotheses on the variance or standard deviation of a normal distribution – Test hypotheses on a population proportion – Conduct tests for goodness of fit – Conduct contingency table tests – Compute power (1 – β) for a sample – Compute a sample size which will obtain a given power • You should be able to understand: – How to structure an engineering decisionmaking problem as a hypothesis test – What a Type I error is – What a Type II error is Chapter 9: Objectives • Although intervals are useful on their own, the main reason it is discussed first is because it forms the basis for hypothesis testing. • Hypothesis testing is designed to answer questions such as: – Is our population mean equal to 6.0 feet? – Is the variance of rivet diameter equal to 0.1mm? – Is the probability of having a defective rivet equal to 0.01? Chapter 9: Comparison with confidence intervals • Although intervals are useful on their own, the main reason it is discussed first is because it forms the basis for hypothesis testing. • Hypothesis testing is designed to answer questions such as: – Is our population mean equal to 6.0 feet? – Is the variance of rivet diameter equal to 0.1mm? – Is the probability of having a defective rivet equal to 0.01? – Is the average GPA of the males at Purdue the same as the average GPA of the females at Purdue? • This last question compares two populations – the population of males at Purdue, and the population of females at Purdue. • It is important not to lose sight of the fact that what we are doing in this chapter is not substantially different from what we did in Chapter 8. We are still taking samples of populations, and using those samples to make inferences about the larger populations. This time, instead of estimating parameters of the population and identify the quality of those estimates, we are determining the likelihood of different statements about the population(s). Chapter 9: Comparison with confidence intervals • The questions we will ask are called statistical hypotheses . • Since we don’t have access to the entire population, we can’t answer questions definitively. The best we can do is assign probabilities to different statements about the population. Statistical hypotheses are actually these statements. We will then use our knowledge about the distributions of estimates of population parameters to assign the probabilities.estimates of population parameters to assign the probabilities....
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 Spring '11
 Jake
 Normal Distribution, Null hypothesis, Statistical hypothesis testing, stdev

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