GRADE 7 CURRICULUM GUIDE

The Bulb Emporium and Lights-R-Us each claim that the mean lifespan for their 20-watt bulbs is 10,000 hours. The lifespan of light bulbs has a distribution that is approximately normal. The Bulb Emporium’s distribution of the lifespan for 20-watt bulbs has a standard deviation of 1,000 hours and Lights-R-Us’ distribution of the lifespan of ................
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