Question

Emissions of sulfur dioxide by industry set off chemical changes in the atmosphere that result in "acid rain." The acidity of liquids is measured by pH on a scale of 00 to 14.14. Distilled water has pH 7.0,7.0, and lower pH values indicate acidity. Normal rain is somewhat acidic, so acid rain is sometimes defined as rainfall with a pH below 5.0.below 5.0.

A sample of 105105 rainwater specimens had mean pH 5.43;5.43; standard deviation 0.54;0.54; and five‑number summary 4.33,4.33, 5.05,5.05, 5.44,5.44, 5.79, 6.81.
A. If the distribution is really (5.43,0.54),N(5.43,0.54), what proportion of observations would be less than 5.05?than 5.05?
Give your answer rounded to four decimal places.
B. If the distribution is really (5.43,0.54)N(5.43,0.54), what proportion of observations would be less than 5.79?than 5.79?
Give your answer rounded to four decimal places.

Answer 1

For the emissions of sulfur dioxide,

A. For a rainwater sample with a mean pH of 5.43 and standard deviation of 0.54, approximately 24.19% of observations would be less than 5.05.

B. Similarly, around 74.86% of observations would be less than 5.79 in the same rainwater sample.