The Price-Earnings Ratios of a Sample of Stocks Have a Mean

question 101

Essay

The price-earnings ratios of a sample of stocks have a mean value of 13.5 and a standard deviation of 2. If the ratios have a mound-shaped distribution, what can we say about the proportion of ratios that fall between:
a. 11.5 and 15.5?
b. 9.5 and 17.5?
c. 7.5 and 19.5?

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Definitions:

Spatial Summation

The process by which multiple synaptic inputs from different locations on the same neuron combine to influence the firing rate or activity of the neuron.

Dendrites

The branched projections of a neuron that act to conduct the electrochemical stimulation received from other neural cells to the cell body.

Back Propagation

Reverse movement of an action potential into the soma and dendritic field of a neuron; postulated to play a role in plastic changes that underlie learning.

Action Potential

A temporary reversal of an electric polarization of the membrane of a nerve cell or muscle cell, allowing for the transmission of signals.