# MS 150 Statistics quiz 13 fall 2007 • Name:

Ohm's law
current/ampsvoltage/volts
0.000.0
0.151.0
0.181.5
0.253.0

Linear regression: On the 15th of November the physical science students measured current and voltage to determine whether a series of circuits with one, two, and three light bulbs obeyed Ohm's law where Voltage V = current i × resistance R. Their data is shown in the table.

1. ______________ Does the relationship between current and voltage appear to be linear, non-linear, or random?
2. ______________ Determine the slope of the linear regression (best fit line) for the data.
3. ______________ Determine the y-intercept of the linear regression for the data.
4. ______________ Determine the correlation coefficient r.
5. ______________ Is the correlation positive or negative?
6. ______________ Is the correlation none, low/weak, moderate, high/strong, or perfect?
7. ______________ Determine the coefficient of determination.
8. ______________ What percent in the variation in current "explains" the variation in voltage?
9. ______________ What would be the predicted voltage for a current of 0.30 amps?
10. ______________ What would be the predicted current for a voltage of 4.5 volts?
Linear regression statistics
Statistic or ParameterSymbolEquationsOpenOffice
Slopeb=SLOPE(y data; x data)
Intercepta=INTERCEPT(y data; x data)
Correlationr=CORREL(y data; x data)
Coefficient of Determinationr2 =(CORREL(y data; x data))^2