问题


There is a single choice question about high school statistics. Answer the question by replying A, B, C or D.
Question: Tina’s science fair project was to estimate the mean amount of chemicals in her city’s water supply. At first, she had decided to use a random sample of 15 observations. But her teacher asked her to take 35 observations. The mean and standard deviation from 35 observations turned out to be approximately the same as those from 15 observations. Is there any advantage in using 35 observations instead of 15 observations?
A. There is no advantage. Because the mean and the standard deviation are about the same, the confidence interval computed using 35 observations should be approximately the same as that computed using 15 observations.
B. There is no advantage. In fact, the 20 extra observations will increase the likelihood of error.
C. There is no advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be wider than that using 15 observations.
D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations.
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0

D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations.
D
deepseekr1

The advantage of using a larger sample size in constructing a confidence interval lies in reducing the standard error, which is inversely proportional to the square root of the sample size (\( \text{Standard Error} = \frac{s}{\sqrt{n}} \)). Even if the mean and standard deviation (\(s\)) remain approximately the same, increasing the sample size (\(n\)) from 15 to 35 decreases the standard error. This results in a smaller margin of error (\( \text{Margin of Error} = \text{Critical Value} \times \text{Standard Error} \)) and thus a **narrower confidence interval**.

- **Option A** is incorrect because it ignores the role of sample size in determining the width of the confidence interval.
- **Option B** incorrectly claims that more observations increase error, whereas larger samples generally reduce sampling variability.
- **Option C** is false since a larger \(n\) makes the confidence interval narrower, not wider.
- **Option D** correctly identifies that the confidence interval will be narrower with 35 observations due to the reduced standard error.

Answer: D
D
gpto1 D D
GPT-4o D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations. D
llama3.1-70B-Instruct

D
D
llama3.1-405B-Instruct

D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations.
D
DeepSeek-Coder-V2 D D
Qwen2-72B-Instruct D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations. D
baichuan4 D D
doubao D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations.

With a larger sample size (35 vs 15), the estimate is more likely to be closer to the true population mean, resulting in a narrower confidence interval and more accurate results.
D
minimax D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations. D
kimi D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations.

This is because the standard error of the mean, which is the standard deviation divided by the square root of the sample size, decreases as the sample size increases. A smaller standard error leads to a narrower confidence interval, indicating that the estimate of the population mean is more precise.
D
wenxinyiyan D D
zhipu D

Explanation: Increasing the sample size generally leads to a more accurate estimate of the population mean and reduces the margin of error in the confidence interval. Even though the mean and standard deviation from the 35 observations are approximately the same as those from the 15 observations, the larger sample size results in a narrower confidence interval. This is because the standard error of the mean decreases as the sample size increases, making the estimate more precise. Therefore, the correct answer is D.
D
gpto1 D D
deepseekv3 D. There is some advantage. Because she took 35 observations instead of 15 observations, the confidence interval using 35 observations will be narrower than that using 15 observations. D