Anindustrial plant dumps its waste into a nearby river, but claims that it is not impacting thenative fishthatlive in the river. You havemeasuredthecalciumconcentration from a randomsample of18locations in the river and calculateda meanof 97.4mg/L, with a standarddeviation of 4.1mg/L.The fish are able to tolerate calcium concentrations up to95mg/L.

a.Assuming a normal distribution, calculate a 95% confidence interval for the meancalcium concentration in the river.

b.Doyour data suggest that the fish are being negatively impacted? Explain your answer.

c.Assuming that you held everything else constant, how would the width of theconfidence interval change if youdoubled your sample size from 18 to 36?Would itbecomewider, narrower, or stay the same?