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Unformatted text preview: [1 point] 1 of 8 ID: MST.HT.TM.01.0020 Dr Carl is a mathematics and statistics lecturer. He is interested in studying a new approach at teaching mathematics and statistics in high school. Recently this new approach has been adopted. It was previously the case that the mean score for all high school students doing their end of year exam was 67, however, the population standard deviation is unknown. The scores of all students are approximately normally distributed. He thinks that, with this new teaching approach, the mean score may have increased. A random sample of 44 scores is gathered and the sample mean and standard deviation calculated. Dr Carl will conduct a hypothesis test using a level of significance of 0.05. Select the correct null and alternate hypotheses for this test: H : μ = 67 H a : μ > 67 H : μ = 67 H a : μ ≠ 67 H : μ > 67 H a : μ = 67 H : μ = 67 H a : μ < 67 [4 points] 2 of 8 ID: MST.CI.CIM.04.0010a Internet company Gurgle is carrying out testing on the efficiency of its search engine. A sample of 50 searches have been carried out and the time taken to display the results has been recorded for each search. The mean search time for the sample was calculated as 0.1498 seconds. The standard deviation of the search times for the sample was calculated as 0.0103 seconds. The population standard deviation of search times is unknown. a)Select all the techniques that are commonly used to construct a confidence interval for the mean when the population standard deviation ( ) is unknown: σ Approximate the population standard deviation ( ) with the sample standard deviation (s) σ Replace the sample size (n) with n1 Decrease the confidence level to compensate for the increased margin of error...
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This note was uploaded on 11/08/2010 for the course STAT 301 taught by Professor Staff during the Spring '08 term at Purdue.
 Spring '08
 Staff
 Statistics

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