The 98% confidence interval for the population mean net gain of the departments is 1640 ± 2.33 * 72.672 = (1470.67 dollars , 1809.33 dollars).
To calculate the confidence interval, we'll use the formula:
Confidence Interval = Sample Mean ± (Critical Value) * (Standard Deviation / √Sample Size)
The critical value for a 98% confidence level can be obtained from the standard normal distribution table, and in this case, it is 2.33 (approximately).
Plugging in the values, we have:
Confidence Interval = 1640 ± 2.33 * (325 / √20)
Calculating the standard error (√Sample Size) first, we get √20 ≈ 4.472.
we can calculate the confidence interval:
Confidence Interval = 1640 ± 2.33 * (325 / 4.472)
Confidence Interval = 1640 ± 2.33 * 72.672
Confidence Interval ≈ (1470.67 dollars , 1809.33 dollars)
Therefore, with a 98% confidence level, we can estimate that the population mean net gain of the departments falls within the range of 1470.67 to 1809.33.
To know more about confidence interval, refer here:
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