A Statistics instructor wanted to compare the scores on the same final exam given to students at a local community college and local university. The Statistics instructor feels that students at the community college would be better prepared and have higher exam scores on the final exam. After grading the final exams from both institutions, the Statistics instructor found that for a sample of 36 community college students, the sample had a mean score of 84 with a standard deviation of 3.4. A sample of 45 university students had a mean score 79 with a standard deviation of 2.6. Construct a 95% confidence interval for the difference between population mean exam scores. Round your final results to one decimal place. 3.7 ? ?cc - ?univ ? 6.4
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Step 1: Calculate the difference between the sample means: 84 - 79 = 5 Show more…
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Suppose the math department chair at a large state university wants to estimate the average overall rating, out of five points, that students taking Introductory Statistics gave their lecturers on their end-of-term evaluations. She selects a random sample of 32 evaluations and records the summary statistics shown. Sample size Sample mean Sample standard deviation Population standard deviation Standard error Confidence level n x̄ s σ σx̄ C 32 3.9102 1.0809 1.0213 0.1805 95% The department chair determines the standard error using σ, the standard deviation calculated from all student evaluations submitted to her department. Assume the Statistics lecturers' ratings have the same standard deviation. Use this information to find the margin of error and the lower and upper bounds of a 95% confidence interval for μ, the mean overall rating students gave their Introductory Statistics lecturers. Round your answers to the nearest hundredth. Margin of error = Lower bound = Upper bound
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