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A researcher wants to know how long it takes, on average, for a certain species of bacteria to divide. She watches 21 cells through a microscope and times how long it takes them to divide. She obtains the following data, in hours: 7.6, 7.6, 7, 7.7, 8.1, 7.6, 8.2, 7.9, 6.9, 7.2, 6.8, 7.3, 7.6, 7.5, 7.3, 7.9, 6.7, 6.6, 7.8, 7, 7.1 Assuming the population standard deviation is or = 0.4, construct a 89% condence interval for the average time it takes this species of bacteria to divide. i= We are 89% condent that this species of bacteria takes, on average, between