Weinstein, McDermott, and Roediger (2010) report that students who were given questions to be answered while studying new material had better scores when tested on the material compared to students who were simply given an opportunity to reread the material. In a similar study, an instructor in a large psychology class gave one group of students questions to be answered while studying for the final exam. The overall average for the exam was
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Chapter 9 Solutions
Statistics for The Behavioral Sciences (MindTap Course List)
- Researchers interested in lead exposure due to car exhaust sampled the blood of 52 police officers subjected to constant inhalation of automobile exhaust fumes while working traffic enforcement in a primarily urban environment. The blood samples of these officers had an average lead concentration of 124.32 µg/l and an SD of 37.74 µg/l; a previous study of individuals from a nearby suburb, with no history of exposure, found an average blood level concentration of 35 µg/l. Write down the hypotheses that would be appropriate for testing if the police officers appear to have been exposed to a higher concentration of lead. Explicitly state and check all conditions necessary for inference on these data. Test the hypothesis that the downtown police officers have a higher lead exposure than the group in the previous study. Interpret your results in context. Based on your preceding result, without performing a calculation, would a 99% confidence interval for the average blood concentration…arrow_forwardA survey among the workers in a large manufacturing company was taken, in order to findout from which company the workers had purchased their mobile phones, and to find outwhether the choice of mobile phone company was related to the type of worker. The resultsare shown in the table below. ls there evidence, at 5% level, that the choice of Phone Company is independent of the type ofworker?arrow_forwardA nationwide study of undergraduate students reported that the mean number of drinks consumed per week during the spring semester is 7.96. The mean number of drinks consumed per week at USC is 7.64 (s.d.=2.55, N=412 Health services is concerned that USC students are consuming significantly more alcohol per week than the national average. Using an alpha level of .05, Is there sufficient evidence to be concerned? Be sure to select the correct critical value for the alternative hypothesis, and then use this evidence to make your conclusionarrow_forward
- A fisheries biologist collected a random sample of fish from a lake and conducted a chi-square goodness-of-fit test to see if the distribution of fish changed over time. The table below shows the distribution of fish that were put into the lake when it was originally stocked. Fish Type Trout Bass Perch Sunfish Catfish Percent 25% 25% 20% 15% 15% The biologist found evidence to reject the null hypothesis in favor of the alternative hypothesis. Which of the following represents the alternative hypothesis of the test?arrow_forwardThe aging Neotropical termites (Neocapritermes taracua) secrete a sticky, blue-colored liquid that they spew to intruding termites. The younger Neotropical termites secrete a liquid that lacks the blue component, so it is white in appearance. In an experiment that measured the toxicity of the blue substance, the researchers placed one drop of either the blue liquid or the white liquid on individuals of a second termite species, Labiotermes labralis. Of the 41 Labiotermes labralis that got the blue drop, 37 were immobilized. Of the 40 Labiotermes labralis that got the white drop, 9 were immobilized. Is the blue liquid toxic compared to the white liquid?arrow_forwardCompare the two separate scatterplots. In particular, how do the associtation compare between women with pets vs. women without pets? Does one group have more variation in systolic blood pressure than the other? If so, for which group? Does systolic blood pressure seem higher for common ages between the two groups? If so, for which group?arrow_forward
- Use the following data to determine if drug B produces higher creatinine levels than drug A, assume the data is normally distributed. Creatinine levels (µmol/L) Drug A Drug B 48.2 52.3 54.6 57.4 58.3 55.6 47.8 53.2 51.4 61.3 52.0 58.0 55.2 59.8 49.1 54.8 49.9 52.6 Write out the null and alternative hypothesis in *words and symbols*. What is the hypothesis in words? Determine the critical value (use a significance level of 0.05) Calculate the test statistic, and determine if the results are significant or not. How did you calculate the standard deviations? Please provide a complete outline of calculationsarrow_forwardIf the value of Cronbach’s alpha is 0.07, it means ___________; a. Research instrument is not reliable b. Research instrument is internally consistent c. Data is reliable d. Data is internally consistentarrow_forwardA series of tests of fire prevention sprinkler systems that use a foaming agent to quell the fire were performed to determine how long it took (in seconds) for the sprinklers to be activated after the detection of a fire by the system. The system has been designed so that the true average activation time is supposed to be at most 25 seconds. Do the data strongly indicate that the design specifications have not been met? The data for the test are given below: 27 41 22 27 23 35 30 33 24 27 28 22 24arrow_forward
- In a study attempting to replicate findings by Stephens, Atkins, & Kingston (2009), each participant was asked to plunge a hand into the icy water and keep it there as long as the pain would allow. In one condition, the participants repeated their favorite curse words while their hands were in the water. In the other condition, they repeated neutral words. The original research showed that, in addition to lowering the participants’ perception of pain, swearing also increased the amount of time they were able to tolerate the pain. Data similar to the results obtained in the study are shown in the following table: _____________Amount of Time (in Seconds)_ Participant Swear Words Neutral Words 1 94 59 2 70 61 3 52 47 4…arrow_forwardIn a study attempting to replicate findings by Stephens, Atkins, & Kingston (2009), each participant was asked to plunge a hand into the icy water and keep it there as long as the pain would allow. In one condition, the participants repeated their favorite curse words while their hands were in the water. In the other condition, they repeated neutral words. The original research showed that, in addition to lowering the participants’ perception of pain, swearing also increased the amount of time they were able to tolerate the pain. Data similar to the results obtained in the study are shown in the following table: _____________Amount of Time (in Seconds)_ Participant Swear Words Neutral Words 1 94 59 2 70 61 3 52 47 4…arrow_forwardA paper investigated the driving behavior of teenagers by observing their vehicles as they left a high school parking lot and then again at a site approximately 1 2 mile from the school. Assume that it is reasonable to regard the teen drivers in this study as representative of the population of teen drivers. Amount by Which Speed Limit Was Exceeded MaleDriver FemaleDriver 1.2 -0.1 1.4 0.4 0.9 1.1 2.1 0.7 0.7 1.1 1.3 1.2 3 0.1 1.3 0.9 0.6 0.5 2.1 0.5 (a) Use a .01 level of significance for any hypothesis tests. Data consistent with summary quantities appearing in the paper are given in the table. The measurements represent the difference between the observed vehicle speed and the posted speed limit (in miles per hour) for a sample of male teenage drivers and a sample of female teenage drivers. (Use μmales − μfemales.Round your test statistic to two decimal places. Round your degrees of freedom down to the nearest whole number. Round your p-value to…arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill