CHAPTER 10 STATS

If the equation for the regression line is y'= 9x+2 , then a value of x= -3 will result in a predicted value for y of

-25

If the equation for the regression line is y=-8x+3 , then the slope of this line is

-8

In a study of reaction times, the time to respond to a visual stimulus (x) and the time to respond to an auditory stimulus (y) were recorded for each of 6 subjects. Times were in thousandths of a second. The results are presented in the following table.The following MINITAB output describes the fit of a linear model to these data. Assume that the assumptions of the linear model are satisfied. What is the slope of the least-squares regression line? Auditory= 193.26291+0.354955

0.354955

If the correlation coefficient r is equal to 0.652, find the coefficient of nondetermination.

0.575

Compute the value of the correlation coefficient. X: 40, 43, 46, 41, 44 Y: 182, 214, 210, 194, 218

0.814

Compute the standard error of the estimate for the data below. Round to the thousandths place. X; 27, 28, 29, 30, 31, 32 Y: 116.95, 120.37, 125.26, 124.90, 129.37, 130.90

1,289

What is the value of y' when x=3, if the equation of the regression line is y'=23.1 - 3.8x ?

11.7

If the equation for the regression line is y=9x-5 , then a value of x=2 will result in a predicted value for y of

13

In a study of reaction times, the time to respond to a visual stimulus (x) and the time to respond to an auditory stimulus (y) were measured recorded for each of 6 subjects. Times were in thousandths of a second. The results are presented in the following table.The following MINITAB output describes the fit of a linear model to these data. Assume that the assumptions of the linear model are satisfied. What is the intercept of the least-squares regression line? Auditory= 240.686515+0.109829

240.686515

If the equation for the regression line is y=-8x+6 , then the intercept of this line is

6

If the correlation coefficient is0.790 , what is the explained variation?

62.4%

Compute the standard error of the estimate for the data below. X: 54, 63, 70, 84, 97 Y: 94, 122, 146, 167, 191

7.47

A correlation coefficient r was calculated to be 0.830 . The coefficient of nondetermination would be 0.170.

False

The rounding rule for the correlation coefficient requires two decimal places.

False

Using a regression line of y'= 17.3 + 3.4x, a value of x=3.6 would result in a predicted value of y'=31.7.

False

If the correlation coefficient r is equal to 0.547, find the coefficient of determination and the coefficient of nondetermination.

The coefficient of determination is 0.299 and the coefficient of nondetermination is 0.701

The prediction interval around y' for a specific x is

a confidence interval for the true mean value of the y values that correspond to that x.

The standard error of the estimate is the standard deviation of the observed x-values about the predicted x' values.

false

The two variables in a scatter plot are called the

independent variable and dependent variable.

The formula for the coefficient of nondetermination is 1.00-r2.

true

A positive relationship exists when both variables increase or decrease at the same time.

True

A regression line can be used to show trends in data.

True

A regression line was calculated as y'= 9.7-3.2x. The slope of this line is -3.2.

True

The population correlation coefficient is computed by using all possible pairs of data values (x,y) taken from a population.

True