A study was commissioned to find the mean weight of the residents in certain town. The study examined a random sample of 142 residents and found the mean weight to be 164 pounds with a standard deviation of 26 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 142 residents and found the mean weight to be 164 pounds with a standard deviation of 26 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:
Understand the problem: Understand the problem and what is being asked.We need to calculate the margin of error for the mean weight of the residents in a town at the 95% confidence level using the normal distribution/empirical rule.
Identify the formula: Identify the formula to calculate the margin of error using the standard deviation and the z-score for the 95% confidence level.The margin of error (E) can be calculated using the formula E=z×(σ/n), where z is the z-score corresponding to the confidence level, σ is the standard deviation, and n is the sample size.
Find the z-score: Find the z-score corresponding to the 95% confidence level.For a 95% confidence level, the z-score is typically 1.96. This value is obtained from a z-table or standard normal distribution table.
Calculate the margin of error: Calculate the margin of error using the given values.We have the standard deviation σ = 26 pounds, the sample size n = 142, and the z-score for 95% confidence z = 1.96.Now, plug these values into the formula:E=z×(σ/n)E=1.96×(26/142)
Perform the calculations: Perform the calculations.First, calculate the denominator:142≈11.916Now, divide the standard deviation by the square root of the sample size:11.91626≈2.181Finally, multiply this result by the z-score:E=1.96×2.181E≈4.275
Round the margin of error: Round the margin of error to the nearest tenth.E≈4.275 rounds to 4.3 when rounded to the nearest tenth.
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