Ackerman and Goldsmith (2011) report that students who study from a screen (phone, tablet, or computer) tended to have lower quiz scores than students who studied the same material from printed pages. To test this finding, a professor identifies a sample n=16 of students who used the electronic version of the course textbook and determines that this sample had an average score of M=72.5 on the final exam. During the previous three years, the final exam scores for the general population of students taking the course averaged μ=77 with a standard deviation of σ=8 and formed a roughly
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Assuming a two-tailed test, state the null hypothesis in a sentence that includes the two variables being examined.
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Using the standard four-step procedure, conduct a two-tailed hypothesis test with α=.05 to evaluate the effect of studying from an electronic screen.
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- The Bureau of Labor Statistics reports that the official unemployment rate for Black people was 10.4% and 4.7% for White people in February 2015. Select all correct answers for this question. O The samples of white and black people are independent. The explanatory variable is the unemployment rate. The response variable is the unemployment rate. The response variable is race.arrow_forwardIdentify whether the studies described here are based on (1) single samples, (2) paired samples, or (3) independent samples. Cardiovascular disease risk factors are compared in husbands and wives. A nutritional exam is applied to a random sample of individuals. Results are compared to the results of the whole nation. An investigator compares vaccination histories in 30 autistic schoolchildren to a simple random sample of non-autistic children from the same school district.arrow_forwardAn owner of an ice cream shop wants to investigate whether a new training program affects the scooping skills of ice cream shop employees. To assess this, the owner divides employees into two groups: those who receive training (CT) and those who do not (NT). The owner evaluates their scooping skills using a scooping proficiency test. The dataset includes the test scores of the NT (no training) group: 15.00, 7.00, 18.00, 10.00, 6.00, and 20.00, and the CT (trained) group: 15.00, 10.00, 14.00, 7.00, 21.00, and 21.00. The owner is aware of the known population mean for scooping proficiency, which is 20. The hypothesis is that employees who did not receive training (NT) will likely have lower scooping proficiency than the population mean. To investigate this hypothesis, the owner conducts a one-sample t-test with a significance level (alpha) set at 0.05. The objective is to determine if the mean scooping proficiency of the NT group is significantly different from the established population…arrow_forward
- In a survey of working parents (both parents working), one of the questions asked was "Have you refused a job, promotion, or transfer because it would mean less time with your family?" 410410 men and 410410 women were asked this question. 26%26% of the men and 19%19% of the women responded "Yes". Based on this survey, can it be concluded that there is a difference in the proportion of men ( p1p1 ) and women ( p2p2 ) responding "Yes"? Use a significance level of α=0.05α=0.05 for the test. Step 3 of 5 : Compute the value of the test statistic. Round your answer to two decimal places.arrow_forwardThe National Cancer Institute conducted a 2-year study to determine whether cancer death rates for areas near nuclear power plants are higher than for areas without nuclear facilities. A spokesperson for the Cancer Institute said, "From the data at hand, there was no convincing evidence of any increased risk of death from any of the cancers surveyed due to living near nuclear facilities." Let p denote the proportion of the population in areas near nuclear power plants who die of cancer during a given year. The researchers at the Cancer Institute have considered the null and alternative hypotheses below: А. Họ: p = value for areas without nuclear facilities Hạ: p> value for areas without nuclear facilities According to the spokesperson's statement, what is the conclusion of the National Cancer Institute? Select one of the following: Reject Ho Fail to reject Ho Reject Ha Fail to reject Haarrow_forwardAcne is a common skin disease that affects most adolescents and can continue into adulthood. A study compared the effectiveness of three acne treatments and a placebo, all in gel form, applied twice daily for 12 weeks. The study's 517 teenage volunteers were randomly assigned to one of the four treatments. Success was assessed as clear or almost clear skin at the end of the 12 week period. The results of the study can be seen in the table below. Using the appropriate statistical test, determine if there is significant evidence that the four treatments perform differently. If so, how do they compare.arrow_forward
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- Researchers have noted a decline in cognitive functioning as people age (Bartus, 1990). However, the results from other research suggest that the antioxidants in foods such as blueberries may reduce and even reverse these age-related declines (Joseph et al., 1999). To examine this phenomenon, suppose that a researcher obtains a sample of n = 16 adults who are between the ages of 65 and 75. The researcher uses a standardized test to measure cognitive performance for each individual. The participants then begin a 2-month program in which they receive daily doses of a blueberry supplement. At the end of the 2-month period, the researcher again measures cognitive performance for each participant. The results show an average increase in performance of MD = 7.4 with SS = 1215. Does this result support the conclusion that the antioxidant supplement has a significant effect on cognitive performance? Use a two-tailed test with α = .05. Show your computations.arrow_forwardIdentify the statistical procedures that are appropriate for the data. Childhood participation in sports, cultural groups, and youth groups appears to be related to improved self-esteem for adolescents (McGee, Williams, Howden-Chapman, Martin & Kawachi, 2006) in a representative study, a researcher compares scores on a standardized self-esteem questionnaire for a sample of n = 100 adolescents with a history of group participation and a separate sample of n = 100 who have no history of group participation.arrow_forward
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