Write True or False.
b. The graphical technique used to describe the relationship between two interval (i.e. quantitative) variables is the scatter diagram.
c. When possible, the best way to establish that an observed association is the result of a cause- and-effect relation is by means of the correlation coefficient.
d. Using the regression equation to make predictions for values of the predictor variable outside the range of the observed values of the predictor variable is called extrapolation.
e. All normal distributions are defined by the mean and standard deviation.
f. The length, X, of a fish from a particular mountain lake in Idaho is normally distributed with μ = 8.7 inches and σ = 1.2 inches. X is a discrete variable.
g. Two t-curves have degrees of freedom 10 and 22 respectively. The one with 10 degrees of freedom more closesly resembles the standard normal curve.
h. The correlation between the daily sales of air conditioners and the daily sales of electric fans in July found to be 0.92. A least squares regression line that predicts daily sales of air conditioners (y) from daily sales of electric fans (x) is fitted to the data. An increase in the daily sales of electric fans causes an increase in the daily sales of air conditioners in July