Statistical Hypothesis Testing Assignment Solutions, Exercises of Psychology

Download Statistical Hypothesis Testing Assignment Solutions and more Exercises Psychology in PDF only on Docsity! Assignment 1. A company is considering purchasing an expensive piece of machinery which it hopes will reduce the amount of time it takes to manufacture its product, but which might actually have the reverse effect and increase (slow down) production time. Currently (without the new machine), it takes an average of 55.5 seconds to manufacture the product. The company decides to test the new machine for a few days to see whether it speeds up or slows down production. a) State the null and the alternative hypotheses that the company wishes to test. b) With α ≤ .05, state the decision rule. c) The company randomly selects 50 of the products made by the new machine and finds that these took an average of 54 seconds to make, with a standard deviation of 6.5 seconds. Test the company's hypotheses and make a decision/conclusion about them. d) Use the sample data from part 'c' to form a 99% confidence interval to estimate the mean time of production of the population of products that could be made by the new machine. 2. A pain reliever currently being used in a hospital is known to bring relief in a mean time of 3.5 minutes. To compare a new pain reliever with the one currently being used, a random sample of 45 patients is given the new drug. The mean time to relief for this sample is 2.8 minutes with a standard deviation of 1.14 minutes. a) Test the research (alternative) hypothesis that the new drug is more effective than the old drug, using α ≤ .05. b) Assuming a standard deviation of 1.14 minutes, approximately how large a sample of patients would be needed to form a 90% confidence interval to estimate the population time-to-relief of the new drug accurate to within plus or minus 10 seconds? 3. The frequency distribution of the heights (measured in feet) of the entire Martian army is as follows: Height Relative Frequency 4 2/5 5 1/5 6 1/5 7 1/5 3a) A squad of 64 Martians is selected at random from the Martian army to train for Docsity.com