Diana wants to play the tuba in a marching band. her goal is to practice 5 hours each week. it is thursday and she has practiced for 3 1/2 hours. how much longer must she practice to meet her weekly goal?

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Aproduction manager test 10 toothbrushes and finds that their mean lifetime is 450 hours. she then design sales package of this type of toothbrush. it states that the customers can expect the toothbrush to last approximately 460 hours. this is an example of what phase of inferential statistics