1. From a population with a variance of 900, a sample of 225 items is selected. At 95% confidence, the margin of error is a. 2 b. 15 >>c. 3.92 d. 4 2. In order to determine an interval for the mean of a population with unknown standard deviation a sample of 61 items is selected. The mean of the sample is determined to be 23. The number of degrees of freedom for reading the t value is a. 22 b. 61 c. 23 >>d. 60 3. If we want to provide a 95% confidence interval for the mean of a population, the confidence coefficient is a. 0.485 b. 1.96 >>c. 0.95 d. 1.645 4. As the number of degrees of freedom for a t distribution increases, the difference between the t distribution and the standard normal distribution a. stays the same b. becomes larger >>c. becomes smaller d. None of these alternatives is correct. 5. The value added and subtracted from a point estimate in order to develop an interval estimate of the population parameter is known as the a. interval estimate b. parameter estimate c. confidence level
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