A study a local high school tried to determine the mean height of females in the US. A study surveyed a random sample of 125 females and found a mean height of 64.5 inches with a standard deviation of 5 inches. Determine a 95% confidence interval for the mean. Confidence Intervalz80%1.28285%1.44090%1.64595%1.96099%2.57699.5%2.80799.9%3.291

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Step 1  Solution:  Given information:  n=125 Sample size   x=64.5 inches Sample mean  s=5 inches sample standard deviation  α=0.05 Level of significance   Step 2  The 95% confidence interval for the mean is  x―±tα2,n−1×sn  n is large we used zα2 instead of tα2,n−1  At α=0.05  zα2=z0.05=1.96 From Z table  (64.5±1.96×5125)  (64.5±1.96×511.180339)  (64.5±1.96×0.4472135)  (64.5±0.8765384)  (64.5−0.8765384,64.5+0.8765384)  (63.62346,65.376538)  (63.62,65.38)  The 95% confidence interval for the mean is ( 63.62, 65.38)

A study a local high school tried to determine the mean height of females in...

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