A study was commissioned to find the mean weight of the residents in certain town. The study examined a random sample of 33 residents and found the mean weight to be 162 pounds with a standard deviation of 35 pounds. At the 95% confidence level, use the normal distribution/empirical rule to estimate the margin of error for the mean, rounding to the nearest tenth. (Do not write ± ).Answer:
Q. A study was commissioned to find the mean weight of the residents in certain town. The study examined a random sample of 33 residents and found the mean weight to be 162 pounds with a standard deviation of 35 pounds. At the 95% confidence level, use the normal distribution/empirical rule to estimate the margin of error for the mean, rounding to the nearest tenth. (Do not write ± ).Answer:
Calculate Z-score: To calculate the margin of error at the 95% confidence level using the normal distribution, we need to use the formula for the margin of error (ME) which is:ME = Z×(σ/n)where Z is the Z-score corresponding to the desired confidence level, σ is the standard deviation, and n is the sample size.
Find Margin of Error Formula: First, we need to find the Z-score that corresponds to the 95% confidence level. For a normal distribution, the Z-score for a 95% confidence level is approximately 1.96. This value is obtained from a Z-table or standard normal distribution table.
Plug in Values: Next, we plug in the values into the margin of error formula:ME=1.96×(3335)
Calculate Square Root: Now, we calculate the square root of the sample size, which is 33.
Divide Standard Deviation: The square root of 33 is approximately 5.7446.
Multiply by Z-score: We then divide the standard deviation by the square root of the sample size: 35/5.7446≈6.0922
Final Margin of Error: Finally, we multiply this result by the Z-score to find the margin of error: ME=1.96×6.0922≈11.9407
Round to Nearest Tenth: Rounding to the nearest tenth, the margin of error is approximately 11.9 pounds.
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