STA 6166 – Exam 1 – Fall 2009 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 meeting the requirement. TRUE 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: 4,8,6,7,10 cm. Give the sample mean, median, and standard deviation of the amounts of growth.- A sample of 5 animals of a particular species is selected at random from the population being managed in a wildlife refuge. If 5% (0.05) of the population have a particular trait, what is the probability that none of the 5 tested have the trait?- Based on the following contingency table, complete the following parts:Among Males, what is Probability of concussion?Among Females, what is Probability of concussion?-A researcher samples 9 computer monitors from each of two manufacturers. The lifetime of each monitor is observed and recorded (in 1000s of hours). The following table gives the summary results:o Test H0: -A2 = -B2 versus HA: -A2 ≠ -B2 at the -------- significance level. 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 1.0 psi with 95% confidence. Based on experience with a similar type of steel, she believes the standard deviation is approximately 6.0 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=170 and TB=130. 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. 16 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=2.4, SD=3.0. Give a 95% confidence interval for thepopulation mean difference.o Does the product placement appear to significantly increase attitude? Yes No- A comparison of 3 drugs was conducted to test whether there are any differences among their effects ofrelieving pain. The mean relief ratings and standard deviations are given below. Each drug was assignedat random to 10 subjects in a completely randomized design (n1=n2=n3=10). H0: ----------------Not all -i are equalo Between Drug Sum of Squares and degrees of freedom:o Within Drug Sum of Squares and degrees of freedom:o F-Statistic _______________________________o Reject H0 (at -=0.05 level) if F-statistic is Above / Below ____________Drug Mean SD1 8 12 10 2 3 12
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