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Exhibit 2-3 Michael's Compute-All, a national computer retailer, has kept a record of the number of laptop computers they have sold for a period of 80 days. Their sales records are shown below: Number of Laptops Sold Number of Days 0 - 19 5 20 - 39 15 40 - 59 30 60 - 79 20 80 - 99 M2 Total 80 27. Refer to Exhibit 2-3. The lower limit of the rst class is