In Exercises 5-20, assume that the two samples are independent simple random samples selected from
- a. Test the given claim using the P-value method or critical value method.
- b. Construct a confidence interval suitable for testing the given claim.
13. Proctored and Nonproctored Tests In a study of proctored and nonproctored tests in an online Intermediate Algebra course, researchers obtained the data for test results given below (based on “Analysis of Proctored versus Non-proctored Tests in Online Algebra Courses,” by Flesch and Ostler, MathAMATYC Educator, Vol. 2, No. 1). Use a 0.01 significance level to test the claim that students taking nonproctored tests get a higher mean than those taking proctored tests.
Group 1 (Proctored): n = 30,
Group 2 (Nonproctored): n = 32,
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- Suppose 10 Texas counties are randomly selected to study the average percent of residents who are wearing a mask. The percentages for these 10 counties are 20 30 48 18 45 51 12 62 35 25 Assuming that the population standard deviation, sigma, is 12, calculate a 95% confidence interval estimate of the mean percent of residents wearing a mask in Texas. 1. 27% - 42% 2. 23% - 46% 3. 24% - 45% 4. 26% - 43%arrow_forwardIn Exercises 1–5, use the following survey results: Randomly selected subjects were asked if they were aware that the Earth has lost half of its wildlife population during the past 50 years. Among 1121 women, 23% said that they were aware. Among 1084 men, 26% said that they were aware (based on data from a Harris poll). Biodiversity When using the given sample data to construct a 95% confidence interval estimate of the difference between the two population proportions, the result of (−0.0659, 0.00591) is obtained from technology. a. Express that confidence interval in a format that uses the symbol <. b. What feature of the confidence interval is a basis for deciding whether there is a significant difference between the proportion of women aware of the statement and the proportion of men who are aware?arrow_forward4. Construct a confidence interval around the sample mean X= 25 for the following conditions:arrow_forward
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- 1. A recent survey showed that from a sample of 500 packages delivered by a Postal Service, 480were delivered on time. a) Construct a 95% confidence interval for the proportion of all packages that are deliveredon time by the Postal Service.arrow_forwardIn a hypothesis test, if the null hypothesis states that the population mean is equal to 100 with a standard deviation of 15, and the sample mean is 108 with a sample size of 36, what is the calculated z-score for this test?arrow_forward
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