# Question: The mean balance of all checking accounts at a bank

The mean balance of all checking accounts at a bank on December 31, 2011, was $850. A random sample of 55 checking accounts taken recently from this bank gave a mean balance of $780 with a standard deviation of $230. Using a 1% significance level, can you conclude that the mean balance of such accounts has decreased during this period? Explain your conclusion in words. What if α = .025?

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