Dave the jogger runs the same route every day (about 2.2 miles). On 18 consecuti

Question

Dave the jogger runs the same route every day (about 2.2 miles). On 18 consecutive days, he recorded the number of steps using a pedometer. The results were

3,129

Construct a 95 percent confidence interval for the true mean number of steps Dave takes on his run.(Round your answers to the nearest whole number.)

What sample size would be needed to obtain an error of ±20 steps with 95 percent confidence? (Round your answer to the nearest whole number.)

Dave the jogger runs the same route every day (about 2.2 miles). On 18 consecutive days, he recorded the number of steps using a pedometer. The results were

Explanation / Answer

Mean=59017/18=3278.7.

S=[(160129.4917)/17]=97.0535.

(a): 95% confidence interval for the true mean number of steps dave takes on his run= [xbar+-[(2.11)(S)/n]]=[3278.7+-[(2.11*97.0535)/18]]=[3278.7+-48.2682]=[3230,3327].

(b): n=((2.11)2S2)/E2=(4.4521*9419.3819)/202=104.84=105.

Therefore, (105-18)=87 sample size would be needed.

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