WorksheetsCh 12 MC Practice
Total questions: 12
Worksheet time: 12mins
Which one of the following provides evidence that a condition for regression inference has been met?
A Normal probability plot of the values for the explanatory variable shows a roughly linear form.
A scatterplot of the residuals against the values of the explanatory variable displays a random scattering of points about the line residuals = 0.
The data consists of at least 30 observations.
Is there a relationship between reaction time and age? A statistics student measures the reaction time of 12 subjects by measuring how far a yardstick drops, in inches, before a subject catches it between his or her thumb and forefinger (a high number thus indicates a slow reaction time). The student plans to use linear regression to see if reaction time can be predicted by the age of the subject. Which one of the following is a correct set of hypotheses for testing the significance of this relationship?
H0: β=1; Ha: β≠1, where β= the true slope of the population regression line.
H0: β=0; Ha: β≠0, where β= the true slope of the population regression line.
H0: ρ=1; Ha: ρ<1, where = the true population correlation between age and reaction time.
The equation of the least-squares regression line is:
y^=2.580+0.30809x
y^=2.580x+0.30809
y^=2.716+0.05051x
Which one of the following is a correct interpretation of the quantity S = 3.06911?
The typical distance between observed reaction times and the mean reaction time is 3.06911 units.
The typical distance between observed ages and the mean age is 3.06911 years.
Predictions of reaction time from age based on this regression model will be off by an average of about 3.0691 units.
Which of the following is the correct decision for the test of H0: β=0 versus Ha: β≠0 at the ∝=.05 level? Assume all conditions for inference have been met.
Because the P-value is less than ∝= .05, we reject H0. There is strong evidence of a linear relationship between age and reaction time.
Because the P-value is 0.365, which is more than ∝= .05, we fail to reject H0. We do not have evidence of a linear relationship between age and reaction time.
Because the P-value is less than ∝= .05, we fail to reject H0. We do not have evidence of a linear relationship between age and reaction time.
ln(B)^= -5.2484+3.0232*ln(D)
ln(B)^=3.0232-5.2484*ln(D)
ln(D)^=3.0232-5.2484*ln(b)
Use the following for #6-8: Sarah runs an ice cream stand at a beach resort, and she is interested in predicting each day’s ice cream sales (in dollars) from the air temperature at 8:00 am (in ○F). She randomly selects 12 days during the previous summer and calculates a least-squares regression of sales on air temperature.
A computer output of her regression is given. Which one of the following is a correct interpretation of the number 1.646?
For each 1○ increase in air temperature, ice cream sales are prediction to increase, on average, by $1.65.
For samples of size 12, the typical deviation of a sample slope from the population (true) slope is estimated to be 1.646.
For this sample, the typical distance between an observed temperature and the mean temperature is 1.646.
At right is a Normal Probability Plot for the residuals from Sarah’s regression. What condition for regression inference is supported by this graph?
The relationship between ice cream sales and air temperature is roughly linear.
The standard deviation of Ice Cream Sales has approximately the same standard deviation for every value of Air Temperature.
Ice Cream Sales is approximately Normally distributed about uy for each value of Air Temperature
Which of the following is a correct expression for the 95% confidence interval for the slope of the population regression equation for the relationship between Air Temperature and Ice Cream sales?
The residual plot at right is for a least-squares linear regression of y = time for completing the new puzzle versus x = the amount of practice time allowed. Based on this residual plot, which one of the following statements must true?
There is a no relationship between Practice Time and Puzzle Completion Time.
This regression equation would likely overestimate the Puzzle Completion Time for 175 minutes of practice time.
There is a non-linear relationship between Practice Time and Puzzle Completion Time.
A scatterplot of the natural logarithm of Completion Time versus Practice Time showed a strongly linear relationship. Which of the following describes the relationship between completion time and practice time?
Completion time is a power function of Practice Time
Completion time is an exponential function of Practice Time.
Completion time is a logarithmic function of Practice Time.
A scatterplot of the base 10 logarithm of Completion Time (in minutes) versus Practice Time (in minutes) showed a strongly linear relationship.
A computer output of the least-squares regression of log10(Completion Time) versus Practice Time is given at right.
Which one of the following is the predicted Completion Time for a student who practices for 150 minutes?
2.6 minutes
8.7 minutes
25.9 minutes
