Estimating Addition and Subtraction Mitchell and his friends went to the candy store, where they can buy candy by the
pound. Mitchell bought 1.2 pounds of candy. His friends bought 2.3 pounds and 1.8
pounds. About how many pounds of candy did they buy altogether?

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Ur environment is very sensitive to the amount of ozone in the upper atmosphere. the level of ozone normally found is 4.04.0 parts/million (ppm). a researcher believes that the current ozone level is not at a normal level. the mean of 2525 samples is 4.44.4 ppm with a standard deviation of 0.80.8. assume the population is normally distributed. a level of significance of 0.020.02 will be used. make the decision to reject or fail to reject the null hypothesis. answer tables