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 0 to 14. Distilled water has pH 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. The pH of rain at one location varies among rainy days according to a Normal distribution with mean 5.43 and standard deviations 0.54. What proportion of rainy days have rainfall with pH below 5.0?

Answer 1

Answer:

The proportion of rainy days that have rainfall with pH below 5.0 is about 0.2294

Explanation:

x < 5.0 corresponds to z < -0.7407, for which Table A gives 0.2294.

p(pH < 5)

$p(z) < \frac{(5 - 5.4)}{0.54}\\ p(z) < -0.7407 = 0.2294$