A foreign company which manufactures electric bulbs has assured its customers that the lifespan of the bulbs is 28 month. Recently the company embarked on a quality improvement research for their product. After the research using new technology, a sample of 70 bulbs was tested and they gave a mean lifespan of 30.2 months with a standard deviation of 4months. Does this justify the research undertaken? the critical value of the one tailed test at 1% level of significance to conduct a statistical test in order to establish the truth about the above question + 2.33. I need answer Thanks

Agroup of student volunteers participates in a study designed to assess several behavioral interventions for improving output in a repetitive task. prior to the beginning of the study, all volunteers unknowingly observed, and their output is measured. at the beginning of the study, prior to any intervention, the volunteers perform the same task under the observation of a study administrator, and their overall output increases. which of the following terms describes this phenomenon? a. simpson's paradox b. hawthorne effect are d. novelty effect d. pygmalion effect e. observer-expectancy effect