Automobile fuel efficiency is often measured in miles that the car can be driven per gallon of fuel (mpg). Heavier cars tend to have lower fuel efficiencies (lower mpg ratings). Which variable (weight or fuel efficiency) is most naturally considered the explanatory (predictor) variable in this context? A. Weight B. Fuel efficiency

Correct option: A. Weight.

Step-by-step explanation:

In regression analysis there are two kinds of variables: Explanatory and Response variable.

The explanatory variable are used to predict the changes in the response variable. They are also known as independent or predictor variable.

The response variable are observed for any changes caused by the explanatory variable. They are also known as the dependent or experimental variable.

In this case it is provided that heavier cars have lower fuel efficiencies.

It implies that there is linear inverse relationship between the variables weight of the car and fuel efficiency.

The response variable is the fuel efficiency and the explanatory variable is the weight of the car. Since the weight of the car is used to determine the fuel efficiency.

Thus, the explanatory variable is the weight of the car.

when functions are first introduced, you will probably have some simplistic "functions" and relations to deal with, usually being just sets of points. these won't be terribly useful or interesting functions and relations, but your text wants you to get the idea of what the domain and range of a function are. small sets of points are generally the simplest sorts of relations, so your book starts with those.

step-by-step explanation:

state the domain and range of the following relation. is the relation a function?

{(2, –3), (4, 6), (3, –1), (6, 6), (2, 3)}

the above list of points, being a relationship between certain x's and certain y's, is a relation. the domain is all the x-values, and the range is all the y-values. to give the domain and the range, i just list the values without duplication:

domain: {2, 3, 4, 6}

range: {–3, –1, 3, 6}

(it is customary to list these values in numerical order, but it is not required. sets are called "unordered lists", so you can list the numbers in any order you feel like. just don't duplicate: technically, repetitions are okay in sets, but most instructors would count off for this.)

while the given set does indeed represent a relation (because x's and y's are being related to each other), the set they gave me contains two points with the same x-value: (2, –3) and (2, 3). since x = 2 gives me two possible destinations (that is, two possible y-values), then this relation is not a function.

note that all i had to do to check whether the relation was a function was to look for duplicate x-values. if you find any duplicate x-values, then the different y-values mean that you do not have a function. remember: for a relation to be a function, each x-value has to go to one, and only one, y-value.

state the domain and range of the following relation. is the relation a function?

{(–3, 5), (–2, 5), (–1, 5), (0, 5), (1, 5), (2, 5)}

i'll just list the x-values for the domain and the y-values for the range: