问题


There is a single choice question about high school statistics. Answer the question by replying A, B, C or D.
Question: The regression analysis of question 20 indicated that "R-sq = 98.1%." Which of the following is (are) true? I. There is a strong positive linear relationship between the explanatory and response variables. II. There is a strong negative linear relationship between the explanatory and response variables. III. About 98% of the variation in the response variable can be explained by the regression on the explanatory variable.
A. I and III only
B. I or II only
C. I or II (but not both) and III
D. II and III only
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0

C. I or II (but not both) and III
C
deepseekr1

The R-squared value of 98.1% indicates that 98% of the variation in the response variable is explained by the regression (Statement III is true). However, R-squared alone does not reveal the direction of the relationship (positive or negative), only its strength. Since the question does not provide the sign of the correlation coefficient or slope, either Statement I (positive) or II (negative) could be true, but not both. Thus, the correct answer combines III with either I or II, depending on the unprovided direction.

**Answer:** C. I or II (but not both) and III
C
gpto1 C C
GPT-4o C. I or II (but not both) and III C
llama3.1-70B-Instruct

C
C
llama3.1-405B-Instruct

C. I or II (but not both) and III
C
DeepSeek-Coder-V2 A C
Qwen2-72B-Instruct C. I or II (but not both) and III C
baichuan4 A C
doubao A

R-sq (R-squared) value of 98.1% indicates a very high goodness of fit, meaning a strong relationship. Without further information about the sign of the slope, we can't determine if it's positive or negative, but we know that about 98% of the variation in the response variable can be explained by the regression on the explanatory variable. So I and III are correct.
C
minimax C. I or II (but not both) and III

The R-squared value (R-sq) indicates the proportion of the variance in the dependent variable that is predictable from the independent variable(s). An R-squared of 98.1% means that approximately 98.1% of the variation in the response variable can be explained by the regression on the explanatory variable. This does not necessarily indicate the direction of the relationship (positive or negative), only the strength of the linear relationship. Therefore, either a strong positive or a strong negative linear relationship could explain this high R-squared value, but not both at the same time.
C
kimi C. I or II (but not both) and III C
wenxinyiyan C. I or II (but not both) and III

Explanation:

The $R^2$ (R-squared) value of 98.1% indicates that about 98% of the variation in the response variable can be explained by the regression on the explanatory variable. This corresponds to statement III, so III is true.

However, the $R^2$ value does not indicate the direction of the relationship (whether it is positive or negative). It only indicates the strength of the linear relationship. The direction (positive or negative) is determined by the regression coefficient (slope) of the explanatory variable. If the slope is positive, there is a positive linear relationship; if the slope is negative, there is a negative linear relationship. Since the question does not provide the slope, we cannot determine whether the relationship is positive or negative, but we know it is strong (due to the high $R^2$ value). Therefore, either I or II (but not both) must be true along with III.
C
zhipu C. I or II (but not both) and III

Explanation:
- "R-sq = 98.1%" indicates that about 98% of the variation in the response variable can be explained by the regression on the explanatory variable, making statement III true.
- The value of R-sq (or R²) does not indicate the direction of the relationship (positive or negative). It only indicates the strength of the relationship. Therefore, either a strong positive linear relationship (I) or a strong negative linear relationship (II) could be true, but not both simultaneously.
Thus, the correct choice is C.
C
gpto1 C C
deepseekv3 The correct answer is **C. I or II (but not both) and III**.

### Explanation:
- **R-sq (R-squared)** is a measure of how well the regression model explains the variation in the response variable. Here, R-sq = 98.1% means that **about 98% of the variation in the response variable can be explained by the regression on the explanatory variable**. This supports statement **III**.
- However, R-squared does not indicate the **direction** of the relationship (positive or negative). The direction depends on the slope of the regression line:
- If the slope is positive, there is a **strong positive linear relationship** (statement I).
- If the slope is negative, there is a **strong negative linear relationship** (statement II).
- Since the slope cannot be both positive and negative simultaneously, **either I or II is true, but not both**.

Thus, the correct answer is **C. I or II (but not both) and III**.
C