Question: A new cell phone battery is being considered as a replacement for the current one. Ten college student cell phone users are selected to try each battery in their usual mix of “talk” and “standby” and to record the number of hours until recharge was needed. (a) Do these results show that the new battery has significantly longer life at α = .05? State your hypotheses and show all steps

clearly. (b) Is the decision close? (c) Are you convinced?

FIGURE 10.17FIGURE 10.18

Excel’s independent sample t tests

Bob May Deno Sri Pat Alexis Scott Aretha Jen Ben

New battery 45 41 53 40 43 43 49 39 41 43

Old battery 52 34 40 38 38 44 34 45 28 33