A study was commissioned to find the mean weight of the residents in certain town. The study examined a random sample of 61 residents and found the mean weight to be 166 pounds with a standard deviation of 37 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 61 residents and found the mean weight to be 166 pounds with a standard deviation of 37 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:
Identify given values: Identify the given values from the problem.Mean (sample mean) = 166 poundsStandard deviation = 37 poundsSample size (n) = 61Confidence level = 95%
Understand confidence level: Understand the 95% confidence level in terms of the empirical rule.The empirical rule, also known as the 68−95−99.7 rule, states that for a normal distribution:- Approximately 68% of the data falls within 1 standard deviation of the mean.- Approximately 95% of the data falls within 2 standard deviations of the mean.- Approximately 99.7% of the data falls within 3 standard deviations of the mean.Since we are interested in the 95% confidence level, we will focus on the range within 2 standard deviations of the mean.
Calculate standard error: Calculate the standard error of the mean (SEM). The standard error of the mean is the standard deviation divided by the square root of the sample size. SEM=nStandard deviationSEM=6137
Perform SEM calculation: Perform the calculation for the standard error of the mean. SEM=6137SEM=7.8102537 (rounded to five decimal places)SEM≈4.7369 (rounded to four decimal places)
Determine margin of error: Determine the margin of error at the 95% confidence level using the empirical rule.Since the empirical rule states that 95% of the data falls within 2 standard deviations of the mean, the margin of error is 2 times the standard error of the mean.Margin of error = 2×SEMMargin of error = 2×4.7369
Calculate margin of error: Perform the calculation for the margin of error.Margin of error = 2×4.7369Margin of error ≈9.4738
Round margin of error: Round the margin of error to the nearest tenth.Margin of error ≈9.5 (rounded to the nearest tenth)
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