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Statistics Class 21 4/23/2012 Quiz 17 When 40 People used the Weight Watchers diet for one year their mean weight loss was 3.0 lb. Assume that the standard deviation of all such wight changes is 𝜎= 4.9 lb and use a 0.01 significance level to test the claim that the mean weight loss is greater than 0. Based on these results does the diet appear to be effective? Does the diet appear to be practical? 𝑥 − 𝜇𝑥 𝑧= 𝜎 𝑛 Testing a Claim about a Mean: 𝜎 Known We first need to make sure we meet the requirements. 1. The sample observations are a simple random sample. 2. The value of the population standard deviation 𝜎 is known 3. Either the Population is normal, or 𝑛 > 30 Test Statistic for Testing a Claim about a Proportion 𝑥 − 𝜇𝑥 𝑧= 𝜎 𝑛 Lets do some examples then, onto the 8-4 Worksheet! Testing a Claim about a Mean: 𝜎 not Known We first need to make sure we meet the requirements. 1. The sample observations are a simple random sample. 2. The value of the population standard deviation 𝜎 is known 3. Either the Population is normal, or 𝑛 > 30 Test Statistic for Testing a Claim about a Proportion 𝑥 − 𝜇𝑥 𝑡= 𝜎 𝑛 Lets do some examples then, onto the 8-5 Worksheet! Testing a Claim about a St.Dev or Variance We first need to make sure we meet the requirements. 1. The sample observations are a simple random sample. 2. The population has a normal distribution. Test Statistic for Testing a Claim about a 𝛔 or 𝝈𝟐 . 2 (𝑛 − 1)𝑠 𝜒2 = 𝜎2 Lets do some examples then, onto the 8-6 Worksheet! Basics of Hypothesis Testing Homework!! 8-4: 1, 3, 7-17 odd 8-5: 1-7 odd, 13-27 odd 8-6: 1-19 odd