In simple linear regression: A The existence of a surrogate variable can explain why two variables have an association without having a causal relationship. B A simple linear regression analysis can prove that there is a causal relationship between two variables. C Both of the above. D Neither of the above.

Step-by-step explanation:

In statistics, a simple linear regression is a method to obtain a formula that helps to predict the values of one variable from another, where there exists a causal behavior. Specifically, through this method, we can say if there's a relation at all, if the correlation is positive or negative, if it's strong or weak.

Therefore, the right answer is B.

it would be 6xy and -16xy.

3

step-by-step explanation:

in standard form:

a= dictionaries

b= maps

you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.

a3+b= 60 (the amount of money you have)

we already know the cost of a=15 so replace a with $15

($15 x 3)+b=60

multiply 15 and 3 to get $45 and replace it with $45

45+b=60

and then replace b with 15 to get the total:

45+15=60

that means you have $15 left after buying 3 dictionaries.

15 divided by the cost of a map ($5) equals 3.

so you can buy 3 maps.

sorry if it was confusing!