Sales from a chain of computer stores are normally distributed, with an average monthly sales volume of $280,560. Estimating the amount of monthly variability in sales is of interest to help anticipate normal income fluctuations. A random sample of 8 months’ sales data yields a standard deviation of $10,423. What is a 98% confidence interval for the standard deviation of monthly sales volume?
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($172,694.71, $666,866.84)
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($6152.47, $21,491.21)
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($6123.96, $27,725.40)
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($6415.73, $24,774.57)