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? Use software or Table A to find the answer.
(Enter your answer rounded to four decimal places.)

Respuesta :

Using the normal distribution, it is found that 0.2119 = 21.19% of rainy days have rainfall with pH below 5.0.

Normal Probability Distribution

The z-score of a measure X of a normally distributed variable with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex] is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

  • The z-score measures how many standard deviations the measure is above or below the mean.
  • Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.

The mean and the standard deviation are given, respectively, by:

[tex]\mu = 5.43, \sigma = 0.54[/tex]

The proportion of rainy days have rainfall with pH below 5.0 is the p-value of Z when X = 5, hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{5 - 5.43}{0.54}[/tex]

Z = -0.8

Z = -0.8 has a p-value of 0.2119.

0.2119 = 21.19% of rainy days have rainfall with pH below 5.0.

More can be learned about the normal distribution at https://brainly.com/question/25800303

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