MA180 Ch10 Reading Quiz

when determining whether there is a correlation between two variables, one should use a _______ to explore the data visually

which of the following statements about correlation is true? -we say there is a positive correlation between x and y if there is no distinct pattern in the scatterplot -we say that there is a positive correlation between x and y if the x-values increase as the corresponding y-values increase -we say that there is a positive correlation between x and y if the x-vales increase as the corresponding y-values decrease -we say that there is a negative correlation between x and y if the x-values increase as the corresponding y-values increase

the _________ measures the strength of the linear correlation between the paired quantitative x- and y-values in a sample

which of the following is NOT a requirement in determining whether there is a linear correlation between two variables -a scatterplot should visually show a straight-line pattern -any outliers must be removed if they are know to be errors -the sample of paired data is a simple random sample of quantitative data -if r>1, then there is a positive linear correlation

which of the following is NOT a property of linear correlation coefficient r? -the value of r is always between -1 and 1 inclusive -the value of r measures the strength of a linear relationship -the value of r is not affected by the choice of x or y -the linear correlation coefficient r is robust. That is, a single outlier will not affect the value of r

which of the following is NOT one of the three common errors involving correlation -the use of data on averages - the conclusion that correlation implies causality -correlation does not imply causality -mistaking no linear correlation with no correlation

given a collection of paired sample data, the _________________ y (hat)= b0+b1x algebraically describes the relationship between the two variables, x and y

which of the following is not equivalent to the other three -independent variable -explanatory variable -predictor value -dependent variable

when making predictions based on regression lines, which of the following is not as a consideration -if the regression equation does not appear to be useful for making predictions, the best predicted value of a variable is its point estimate - use the regression for predictions only if the linear correlation coefficient r indicates that there is a linear correlation between the points reasonably well -use the regression equation for predictions only if the graph of the regression line on the scatterplot confirms that the regression line fits the points reasonably well -us the regression line for predictions only if the data go beyond the scope of the available sample data

in a scatterplot, a(n) __________ is a point far away from the other data points

for a pair of sample x- and y-values, the ___________ is the difference between the observed sample value of y and the y-vale that is predicted by using the regression equation

a straight line satisfies the ______________________ if the sum of the squares of the residuals is the smallest sum possible

the coefficient of determination, r squared, is the amount of variation in ___ that is explained by the regression line

a __________________ is an interval estimate of a predicted value of y

the _______ deviations is the vertical distance y(hat)- y(bar), which is the distance between the predicted y-value and the horizontal line passing through the sample mean y (bar)