A researcher tests the effectiveness of an anti-anxiety drug by recruiting 500 participants and randomly assigning half of the participants to take Drug A for 1 month and the other half to take a placebo for 1 month. At the end of the month, anxiety levels are recorded. Overall, participants who received Drug A had anxiety scores of M = 32.12, SD = 10.58 and those you received the placebo had anxiety scores of M = 34.29. SD = 11.10, t(498) = 2.17, p = .01 (one tailed), d = .19. Faced with these data, the researcher needs to write a report in which she interprets the data. Which of the following is the best summary of these data? The results of the t-test are statistically significant, indicating that the drug is much more effective than the placebo. The results of the t-test are significant, but the effect size is small. This study should be replicated with a larger sample size to increase statistical power. The results of the t-test are significant, but the effect size is small. The drug does lower anxiety, but it is not clear if the reduction is enough to warrant use of the drug. The small p value and the small effect size suggest that the observed difference between the drug and placebo groups are likely to be due to sampling error. This study should be replicated with a larger sample size. "The p value is very low, showing that there is only a 1% chance of a Type I error. We can be 99% confident that the drug significantly reduces anxiety."
A researcher tests the effectiveness of an anti-anxiety drug by recruiting 500 participants and randomly assigning half of the participants to take Drug A for 1 month and the other half to take a placebo for 1 month. At the end of the month, anxiety levels are recorded. Overall, participants who received Drug A had anxiety scores of M = 32.12, SD = 10.58 and those you received the placebo had anxiety scores of M = 34.29. SD = 11.10, t(498) = 2.17, p = .01 (one tailed), d = .19. Faced with these data, the researcher needs to write a report in which she interprets the data. Which of the following is the best summary of these data?
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The results of the t-test are statistically significant, indicating that the drug is much more effective than the placebo. |
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The results of the t-test are significant, but the effect size is small. This study should be replicated with a larger |
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The results of the t-test are significant, but the effect size is small. The drug does lower anxiety, but it is not clear if the reduction is enough to warrant use of the drug. |
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The small p value and the small effect size suggest that the observed difference between the drug and placebo groups are likely to be due to sampling error. This study should be replicated with a larger sample size. |
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"The p value is very low, showing that there is only a 1% chance of a Type I error. We can be 99% confident that the drug significantly reduces anxiety." |
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