STA 6166 – Exam 1 – Fall 2010 PRINT Name ___________________________- A quality engineer in a factory is interested in the proportion of all computer chips that her assembly lineproduces that meet a particular quality requirement. She selects a sample of 100 chips and finds that 85 pass the test. This means that -=0.85 is the proportion of all chips the assembly line produces that meet the requirement. TRUE or FALSE- A plant researcher has measured the amount of growth among five plants that received a growth formula. He finds that the amounts of growth were: 16, 20, 24, 18, 22 cm. Give the sample mean, median, and standard deviation of the amounts of growth.- A sample of 6 animals of a particular species is selected at random from the population being managed in a wildlife refuge. If 15% (0.15) of the population have a particular trait, what is the probability that none of the 6 tested have the trait?- A new simpler (LA) test for bird flu is compared with the existing gold standard (HI) test, with the following results. Assume the gold standard (HI) test is completely accurate:What is the probability a person with the bird flu tests positive on the LA test? _____________________What is the probability a person without the bird flu tests negative on the LA test? _____________________-A researcher samples 7 adult males from each of two species of squirrels and measures their body mass index . The following table gives the summary results:o Test H0: -A2 = -B2 versus HA: -A2 ≠ -B2 at the -------- significance level.NOT APPLICABLE (YET) for Fall 2011 Test Statistic: __________________________ Rejection Region: ___________________________ Conclusion (circle best answer):-Conclude -A2 > -B2 -Conclude -A2 < -B2 -Do not reject H0: -A2 = -B2o Test H0: -A= -B versus HA: -A ≠ -B at the -------- significance level (assuming equal variances). Test Statistic: Rejection Region: ___________________________ Conclusion (circle best answer):-Conclude -A > -B -Conclude -A < -B -Do not reject H0: -A = -B-A scientist wishes to estimate the mean breaking strength of a certain type of steel rod within 3.0 psi with 95% confidence. Based on experience with a similar type of steel, she believes the standard deviation is approximately 15.0 psi in individual breaking strengths. How many steel rods should she test?-A comparison is being made to compare the amounts of food eaten per week between two bird species. Samples of 12 males from each species were observed and the amount of food consumed by each bird ina one-week period was recorded. Due to a few extreme outliers, it was decided to use the Wilcoxon Rank-Sum test. The rank sums for species A and B were TA=165 and TB=135. Use the normal approximation to test whether the population medians differ. H0: MedianA = MedianB HA: MedianA ≠ MedianB (Note: Under H0 the standard deviation of TA = 17.32) - Expected Value of TA under null hypothesis = ______________________- Test Statistic: ___________________________________________- P-Value: ______________________________________________- A study was conducted to determine whether consumers’ attitudes toward a product changedafter seeing the product placed (subtly) in a short film. 9 Subjects were given a list of brands,and asked to give a rating to each (pre-viewing). After seeing the film, they were asked again torate the brands. Higher ratings mean stronger preference. The mean and standard deviation ofthe differences (post-pre) were: mean=3.6, SD=1.2. Give a 95% confidence interval for thepopulation mean difference.o Does the product placement appear to significantly increase attitude? Yes No- A chemist is interested in the mean and variance of batches of a compound received from a supplier. Arandom sample of n=18 batches are obtained and the amount of the compound is measured from eachbatch. The sample mean and standard deviation are 23.8 ounces and 0.8 ounces, respectively.o Give a 95% confidence interval for the mean amount among all batches from this supplier.o Give a 95% confidence interval for the standard deviation among all batches from this supplier.NOT APPLICABLE (YET) for Fall
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