mean monthly cell phone bill is different today. The null hypothesis is not rejected. A. There is not sufficient evidence to conclude that the mean monthly cell phone bill is different from its level three years ago of $49.62. B. There is sufficient evidence to conclude that the mean monthly cell phone bill is different from its level three years ago of $49.62. C. There is sufficient evidence to conclude that the mean monthly cell phone bill is higher than its level three years ago of $49.62.
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