Problem

Construct the lower bound of a confidence interval using the following information: n=18; mean = 51.056; standard deviation =32.288; alpha =0.05. Remember that alpha =0.05 is for a 95% confidence interval and alpha =0.01 is for a 99% confidence interval.

Answer

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Answer

Final Answer: The lower bound of the 95% confidence interval is 36.14.

Steps

Step 1 :Given the following information: sample size n=18, mean =51.056, standard deviation =32.288, and alpha =0.05. Remember that alpha =0.05 is for a 95% confidence interval.

Step 2 :To construct the lower bound of a confidence interval, we need to use the formula: mean - Z * (standard deviation / sqrt(n)), where Z is the Z-score corresponding to the desired confidence level.

Step 3 :For a 95% confidence interval, the Z-score is approximately 1.96.

Step 4 :Substitute the given values into the formula to find the lower bound of the confidence interval: 51.0561.96(32.288/18).

Step 5 :Calculate the above expression to get the lower bound of the confidence interval, which is approximately 36.14.

Step 6 :Final Answer: The lower bound of the 95% confidence interval is 36.14.

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