A sheet of stickers has 60 total stickers on it. Some of the stickers are donuts and some are ice cream cones. There are 9 donut stickers for every 3 ice cream cone stickers. How many of the stickers are donut stickers?

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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