In a sample of 12 participants,a researcher estimates the 80% CI for a sample with a mean of M = 22.3 and an estimated standard error (S_M)of 4.7.What is the confidence interval at this level of confidence? A) 80% CI 12.1, 32.5 B) 80% CI 17.6, 27.0 C) 80% CI 15.9, 28.7 D) there is not enough information to answer this question

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Quizplus · Accepted Answer

The 80% confidence interval is calculated as the sample mean plus or minus the margin of error, which is the product of the estimated standard error and the critical value from the t-distribution with 11 degrees of freedom (n-1) and a confidence level of 80%. The critical value is 1.314, so the margin of error is 4.7 * 1.314 = 6.183. The confidence interval is therefore 22.3 +/- 6.183, or (15.9, 28.7).

In a Sample of 12 Participants,a Researcher Estimates the 80