Question

Salts of the perchlorate ion, (ClO₄^-) are widely used in fireworks, but it is of concern as an environmental contaminant: chronic exposure to low levels of perchlorate can cause thyroid disorders. The perchlorate concentration in one river was measured nine times, with a standard deviation of 2.5 ppm. The perchlorate concentration in another river was measured seven times, with a standard deviation of 1.4 ppm. Use the F-test to determine if you can say that these standard deviations are significantly different with 95% confidence.

Answer 1