level of confidence help

Under the old
system the warehouse managers estimated that they were losing an average of $647 worth of
merchandise to thieves each week. A random sample of 60 weekly records under the current
system showed that they were still losing an average of x = $630 worth of merchandise each
week. It is known that the population standard deviation is $92. Does this indicate that the
average loss each week is less than the previous $647 per week? Use a 1% level of significance.
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