Stats Unit 11 Test
A linear regression model was fit to a set of data containing 18 observations. The computer output of the regression analysis is shown in the table. TermCoefCoefSE CoefSE CoefTTConstant12.005.432.210xx0.6940.2412.880 Assume the conditions for regression are met. Which of the following defines the margin of error when a 95 percent confidence interval for the slope of the least-squares regression line is calculated?
look up
Raoul performed an experiment using 16 windup rubber band single-propeller airplanes. He wound up the propeller a different number of times and recorded the amount of time (in seconds) that the airplane flew for each number of rotations that the propeller was wound. A regression analysis was performed and the partial computer output is given below.`
pic n look up
Assuming that all conditions for inference are met, which of the following is an appropriate test statistic for testing the null hypothesis that the slope of the population regression line equals 0 ?
see pics
formula for est
stat+/-(crit value)(se)
Rsq
what percent of variation can be explained by
R
Random, come from sample or experiment
power
(logx,y)
exponential
(x,logy)
linear
(x,y)
A restaurant manager collected data to predict monthly sales for the restaurant from monthly advertising expenses. The model created from the data showed that 36 percent of the variation in monthly sales could be explained by monthly advertising expenses. What was the value of the correlation coefficient?
.6
There is a linear relationship between the number of chirps made by the striped ground cricket and the air temperature. A least squares fit of some data collected by a biologist gives the model ŷ = 25.2 + 3.3x 9 < x < 25, where x is the number of chirps per minute and ŷ is the estimated temperature in degrees Fahrenheit. What is the estimated increase in temperature that corresponds to an increase of 5 chirps per minute?
16.5
A scientist is investigating whether percent concentration can be used to predict density in apple juice. A scientist selected a random sample of 12 apple juice varieties and recorded the density, in pounds per cubic inch, and the percent concentration of each apple juice variety. The scientist wants to estimate the mean change in the density, in pounds per cubic inch, for each increase of 1 percent concentration of apple juice. Assuming the conditions for inference have been met, which of the following inference procedures is most appropriate for this investigation?
A linear regression tt-interval for slope
A car retailer wanted to see if there is a linear relationship between overall mileage and the suggested retail price of a car. The retailer collected data on 18 cars of a similar type selected at random and used the data to test the claim that there is a linear relationship. The following hypotheses were used to test the claim. H0:β1=0Ha:β1≠0H0:β1=0Ha:β1≠0 The test yielded a tt-value of 2.186 with a corresponding pp-value of 0.044. Which of the following is the correct interpretation of the pp-value?
B If there is not a linear relationship between overall mileage and the suggested retail price of a car, the probability of observing a test statistic at least as extreme as 2.186 is 0.044.
Ha
B=/0 linear, B>0, B<0 (pos/neg)
Ho
B=0
A seafood festival organizer is interested in whether there is a relationship between the number of ingredients in the clam chowders that are entered in the festival's clam chowder contest and the ratings given to the chowders by the judges. The organizer requires each of the twelve restaurants in the competition to list all of its chowder's ingredients and requires each judge who tastes the clam chowders to rate each chowder from one through ten on a note card. The organizer then randomly selects twenty-five note cards. Assuming that all conditions for inference are met, which of the following significance tests should be used to investigate whether having more ingredients in the chowders is associated with a reduction in the ratings given to the chowders by the judges?
D A linear regression tt-test for slope
E
Equal Variance- Standard dev of y must be same for all values of x, check residual plot
A doctor recorded the number of miles walked each day by patients over age 60 and the number of doctor visits in a year for 40 patients. The resulting data were used to conduct a hypothesis test to determine whether there is a linear relationship between the number of miles walked and the number of doctor visits. What are the correct hypotheses for the test?
H0:β1=0Ha:β1≠0
I
Independant 10x only sample
Condition
LINER
Test
Lin reg T etst
L
Linear, check scatterplot
N
Normal- Check histogram of residuals, if greater than 30 dont matter as much
A 90 percent confidence interval for the slope of a regression line is determined to be (-0.181, 1.529). Which of the following statements must be true?
The correlation coefficient of the data is positive.
When computing a confidence interval for the slope of a regression line, a plot of the residuals versus the fitted values can be used to check which of the following conditions?
The standard deviation of yy does not vary as xx varies.
A random sample of 15 college soccer players were selected to investigate the relationship between heart rate and maximal oxygen uptake. The heart rate and maximal oxygen uptake were recorded for each player during a training session. A regression analysis of the data was conducted, where heart rate is the explanatory variable and maximal oxygen uptake is the response variable. If a 95 percent confidence interval is constructed for the slope of the population regression line, which of the following is a condition that must be checked?
The true relationship between heart rate and maximal oxygen uptake is linear.
