Questions from Essentials of Statistics

Q: Assume that the variables under consideration satisfy the assumptions for regression inferences

Assume that the variables under consideration satisfy the assumptions for regression inferences. What statistic is used to estimate a. the y-intercept of the population regression line? b. the slope o...

Q: Polychlorinated biphenyls (PCBs), industrial pollutants, are known to be

Polychlorinated biphenyls (PCBs), industrial pollutants, are known to be carcinogens and a great danger to natural ecosystems. As a result of several studies, PCB production was banned in the United S...

Q: The magazine Consumer Reports publishes information on automobile gas mileage and variables

The magazine Consumer Reports publishes information on automobile gas mileage and variables that affect gas mileage. In one issue, data on gas mileage (in mpg) and engine displacement (in liters, L) w...

Q: J. Greene and J. Touchstone conducted a study on the

J. Greene and J. Touchstone conducted a study on the relationship between the estriol levels of pregnant women and the birth weights of their children. Their findings, “Urinary Tract Estriol: An Index...

Q: The ability to estimate the volume of a tree based on a

The ability to estimate the volume of a tree based on a simple measurement, such as the diameter of the tree, is important to the lumber industry, ecologists, and conservationists. Data on volume, in...

Q: Explain why the predictor variable is useless as a predictor of the

Explain why the predictor variable is useless as a predictor of the response variable if the slope of the population regression line is 0.

Q: For two variables satisfying Assumptions 1–3 for regression inferences,

For two variables satisfying Assumptions 1–3 for regression inferences, the population regression equation is y = 20 − 3.5x. For samples of size 10 and given values of the predictor variable, the dist...

Q: Consider the standardized variable / a. Identify its distribution

Consider the standardized variable a. Identify its distribution. b. Why can’t it be used as the test statistic for a hypothesis test concerning β1? c. What statistic is used? What is the distribution...

Q: In this section, we used the statistic b1 as a basis

In this section, we used the statistic b1 as a basis for conducting a hypothesis test to decide whether a regression equation is useful for prediction. Identify two other statistics that can be used a...

Q: a. Decide, at the 10% significance level, whether

a. Decide, at the 10% significance level, whether the data provide sufficient evidence to conclude that x is useful for predicting y. b. Find a 90% confidence interval for the slope of the population...