问题


There is a single choice question about high school statistics. Answer the question by replying A, B, C or D.
Question: Suppose the correlation between two variables is r = 0.19. What is the new correlation if 0.23 is added to all values of the x-variable, every value of the y-variable is doubled, and the two variables are interchanged?
A. 0.19
B. 0.42
C. 0.84
D. -0.19
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0

A
Explanation: Adding a constant to every value of one variable and multiplying every value of the other variable by a constant does not change the correlation. Interchanging the variables will change the sign of the correlation.
A
deepseekr1

The correlation coefficient (r) measures the linear relationship between variables and is unaffected by specific transformations:
1. **Adding a constant to a variable** (e.g., +0.23 to all x-values) does not alter the correlation, as it shifts values without affecting their covariation.
2. **Multiplying a variable by a positive constant** (e.g., doubling all y-values) scales the data but preserves the strength and direction of the relationship. The covariance and standard deviations scale proportionally, leaving r unchanged.
3. **Interchanging variables** (x and y) has no effect because correlation is symmetric.

Since none of these transformations change the correlation coefficient, the new correlation remains **0.19**.

**Answer:** A. 0.19
A
gpto1 A A
GPT-4o A. 0.19 A
llama3.1-70B-Instruct

A
A
llama3.1-405B-Instruct

A
The best answer is A
A
DeepSeek-Coder-V2 D. -0.19 A
Qwen2-72B-Instruct A. 0.19 A
baichuan4 D. -0.19 A
doubao A

Adding a constant to one variable or multiplying a variable by a constant or interchanging the variables does not change the correlation coefficient. So the correlation remains 0.19.
A
minimax The correlation coefficient (r) measures the strength and direction of a linear relationship between two variables on a scatterplot. The value of r is the same, regardless of which variable you call x and which you call y. Therefore, if you interchange the variables, the correlation coefficient will not change.

Adding or subtracting a constant to one of the variables does not change the correlation coefficient because correlation is unaffected by changes in the location of the data. Similarly, multiplying one of the variables by a constant (in this case, doubling the y-values) will only affect the correlation coefficient by the absolute value of that constant. However, since the y-values are being doubled, the correlation coefficient will be multiplied by the square root of that constant (in this case, the square root of 2).

So, the new correlation coefficient will be:

r_new = r * sqrt(2) * sign(0.23)

Since 0.23 is positive, the sign function will return +1, and the square root of 2 is approximately 1.414. Therefore:

r_new = 0.19 * 1.414
r_new ≈ 0.26866

None of the options provided (A, B, C, or D) match the calculated value. However, if we round the value to two decimal places, we get 0.27, which is still not among the options. It seems there might be an error in the options provided or in the interpretation of the question. If we strictly follow the options given, none of them is correct based on the calculations.
A
kimi A. 0.19

Adding a constant to one variable (in this case, adding 0.23 to all values of the x-variable) does not change the correlation coefficient. Multiplying one variable by a constant (doubling the y-variable) changes the correlation coefficient by the same factor as the constant. However, since the correlation is being interchanged, the sign of the correlation coefficient will change if the variables were originally positively correlated, and vice versa.

Since the original correlation coefficient is 0.19, which is positive, and the variables are being interchanged, the new correlation coefficient will be the negative of the original, which is -0.19. However, since we are not changing the sign by the interchange (because the original correlation is positive), the new correlation coefficient remains the same, which is 0.19.
A
wenxinyiyan A. 0.19

Explanation:
Adding a constant to all values of the x-variable and/or multiplying all values of the y-variable by a constant does not change the correlation between x and y. These transformations are called affine transformations, and they preserve the linear relationship (and thus the correlation) between the variables.

Interchanging the variables (i.e., making x the dependent variable and y the independent variable, or vice versa) does not change the absolute value of the correlation but may change its sign. However, in this case, since the original correlation was given as a numerical value (0.19) rather than a signed numerical value, we assume it is positive. Therefore, interchanging the variables does not affect the correlation value.

Hence, the new correlation is still 0.19.
A
zhipu A. 0.19

Explanation:
The correlation coefficient \( r \) is a measure of the linear relationship between two variables and is unaffected by changes in the scale or location of the variables. Specifically:

1. Adding a constant (0.23) to all values of the x-variable does not affect the correlation.
2. Doubling all values of the y-variable also does not affect the correlation.
3. Interchanging the two variables does not change the correlation.

Therefore, the new correlation remains the same as the original correlation, which is 0.19. Hence, the correct answer is A.
A
gpto1 A A
deepseekv3 The correlation coefficient \( r \) measures the strength and direction of a linear relationship between two variables. It is unaffected by:

1. **Adding a constant to all values of one variable**: Adding 0.23 to all values of the \( x \)-variable does not change the correlation.
2. **Scaling a variable by a positive constant**: Doubling all values of the \( y \)-variable does not change the correlation.
3. **Interchanging the variables**: Swapping the \( x \) and \( y \) variables does not change the correlation.

Since none of these operations alter the correlation, the new correlation remains **0.19**.

**Answer: A. 0.19**
A