If We Model After-Tax Household Income with a Normal Distribution

question 22

Multiple Choice

If we model after-tax household income with a normal distribution, then the figures of a 1995 study imply the information in the following table. Assume that the distribution of incomes in each country is normal, and round all percentages to the nearest whole number. What percentage of Sweden households had an income of $50,000 or more $\begin{array} { | l | l | l | l | l | l | } \hline \text { Country } & \text { U.S. } & \text { Canada } & \text { Switzerland } & \text { Germany } & \text { Sweden } \\\hline \begin{array} { l } \text { Mean } \\\text { household } \\\text { income }\end{array} & \$ 38,000 & \$ 35,000 & \$ 39,000 & \$ 34,000 & \$ 32,000 \\\hline \begin{array} { l } \text { Standard } \\\text { deviation }\end{array} & \$ 21,000 & \$ 17,000 & \$ 16,000 & \$ 14,000 & \$ 11,000 \\\hline\end{array}$

• A)22%
• B) 95%
• C) 4%
• D) 89%
• E) 5%

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Definitions:

Bicarbonate Ions

Chemical ions (HCO3-) that act as a major component of the blood's buffering system, helping to maintain the body's pH balance.

Carbonic Acid

A weak acid formed when carbon dioxide dissolves in water, playing a vital role in regulating pH in the blood.

Respiratory Acidosis

A condition occurring when the lungs cannot remove all of the carbon dioxide the body produces, causing body fluids, especially the blood, to become too acidic.

Expiratory Neurons

Neurons involved in the control of the muscles responsible for expelling air from the lungs.