Concept explainers
Using the model fit to the data of Exercise 11.8, construct a 95% confidence interval for the
11.8 Laboratory experiments designed to measure LC50 (lethal concentration killing 50% of the test species) values for the effect of certain toxicants on fish are run by two different methods. One method has water continuously flowing through laboratory tanks, and the other method has static water conditions. For purposes of establishing criteria for toxicants, the Environmental Protection Agency (EPA) wants to adjust all results to the flow-through condition. Thus, a model is needed to relate the two types of observations. Observations on toxicants examined under both static and flow-through conditions yielded the data in the accompanying table (measurements in parts per million, ppm). Fit the model
- a What interpretation can you give to the results?
- b Estimate the flow-through value for a toxicant with an LC50 static value of x = 12 ppm.
11.18
- a Calculate SSE and S2 for Exercise 11.8.
- b Refer to Exercise 11.8. Code the x-values in a convenient manner and fit a simple linear model to the LC50 measurements presented there. Compute SSE and compare your answer to the result of part (a).
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Mathematical Statistics with Applications
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- The relationship between "strength" and "fineness" of cotton fibers was the subject of a study that produced the following data. (Give your answers correct to two decimal places.) x, Strength 76 69 71 76 83 72 78 74 80 82 y, Fineness 4.5 4.5 4.7 4.2 4.1 4.2 4.8 4.9 4.3 4.5 (a) Find the 98% confidence interval for the mean measurement of fineness for fibers with a strength of 79. Lower Limit Upper Limit (b) Find the 90% prediction interval for an individual measurement of fineness for fibers with a strength of 79. Lower Limit Upper Limitarrow_forwardIn a study examining the effect of alcohol on reaction time, Liguori and Robinson (2001) found that even moderate alcohol consumption significantly slowed response time to an emergency situation in a driving simulation. In a similar study, researchers measured reaction time 30 minutes after participants consumed one 6-ounce glass of wine. Again, they used a standardized driving simulation task for which the regular population averages μ = 400 msec. The distribution of reaction times is approximately normal with σ = 40. Assume that the researcher obtained a sample mean of M = 422 for the n = 25 participants in the study. a. Are the data sufficient to conclude that the alcohol has a significant effect on reaction time? Use a two-tailed test with α = .01.arrow_forwardIn a study examining the effect of alcohol on reaction time, Liguori and Robinson (2001) found that even moderate alcohol consumption significantly slowed response time to an emergency situation in a driving simulation. In a similar study, researchers measured reaction time 30 minutes after participants consumed one 6-ounce glass of wine. Again, they used a standardized driving simulation task for which the regular population averages μ = 400 msec. The distribution of reaction times is approximately normal with σ = 40. Assume that the researcher obtained a sample mean of M = 422 for the n = 25 participants in the study A) Are the data sufficient to conclude that the alcohol has a significant effect on reaction time? Use a two-tailed test with α = .01. B) Do the data provide evidence that the alcohol significantly increased reaction time? Use a one-tailed test with α = .01 C) Compute Cohen’s d to estimate the size of the effect.arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill