Correlation Coefficient Calculation

Oct 13, 2025 by wbrum.org 83 views

Analyzing the Relationship Between Word Count and Essay Scores in a Timed Writing Contest

In a timed writing contest, the ability to produce high-quality essays within a limited timeframe is crucial. Ms. Sutton, a teacher, conducted a study to analyze the relationship between word count and essay scores. The data collected from the top ten essays in the contest provides valuable insights into the factors that contribute to a winning essay. In this article, we will delve into the data and explore the relationship between word count and essay scores.

The table below shows the word counts and scores of the top ten essays in the timed writing contest.

Essay Rank	Word Count	Score
1	250	95
2	220	92
3	280	90
4	200	88
5	240	86
6	260	84
7	230	82
8	270	80
9	210	78
10	290	76

To analyze the relationship between word count and essay scores, we can use correlation analysis. The correlation coefficient measures the strength and direction of the linear relationship between two variables. In this case, we want to examine the relationship between word count and essay scores.

Essay Rank	Word Count	Score
1	250	95
2	220	92
3	280	90
4	200	88
5	240	86
6	260	84
7	230	82
8	270	80
9	210	78
10	290	76

Using a correlation analysis, we can calculate the correlation coefficient between word count and essay scores. The correlation coefficient is a value between -1 and 1 that measures the strength and direction of the linear relationship between two variables.

Correlation Coefficient Calculation

To calculate the correlation coefficient, we can use the following formula:

r = Σ[(xi - x̄)(yi - ȳ)] / (√[Σ(xi - x̄)²] * √[Σ(yi - ȳ)²])

where xi and yi are the individual data points, x̄ and ȳ are the means of the two variables, and r is the correlation coefficient.

Plugging in the values from the table, we get:

r = Σ[(250 - 240)(95 - 84)] / (√[Σ(250 - 240)²] * √[Σ(95 - 84)²]) = Σ[10 * 11] / (√[Σ10²] * √[Σ11²]) = 110 / (√[100] * √[121]) = 110 / (10 * 11) = 110 / 110 = 1

Interpretation of the Correlation Coefficient

The correlation coefficient is 1, indicating a perfect positive linear relationship between word count and essay scores. This means that as the word count increases, the essay score also increases.

In conclusion, the data collected from the top ten essays in the timed writing contest shows a strong positive correlation between word count and essay scores. This suggests that producing high-quality essays within a limited timeframe is crucial for success in a timed writing contest. The correlation coefficient of 1 indicates a perfect positive linear relationship between word count and essay scores.

While this study provides valuable insights into the relationship between word count and essay scores, there are some limitations to consider. The sample size is relatively small, with only ten essays included in the analysis. Additionally, the study only examines the relationship between word count and essay scores, and does not consider other factors that may contribute to a winning essay.

Future research could build on this study by examining the relationship between word count and essay scores in a larger sample size. Additionally, researchers could investigate other factors that contribute to a winning essay, such as grammar, syntax, and content.

Sutton, M. (2023). Timed Writing Contest Data. Unpublished dataset.

The data used in this study is available in the appendix.
Frequently Asked Questions About the Relationship Between Word Count and Essay Scores

In our previous article, we explored the relationship between word count and essay scores in a timed writing contest. The data collected from the top ten essays in the contest provided valuable insights into the factors that contribute to a winning essay. In this article, we will answer some of the most frequently asked questions about the relationship between word count and essay scores.

Q: What is the correlation coefficient, and how is it calculated?

A: The correlation coefficient is a value between -1 and 1 that measures the strength and direction of the linear relationship between two variables. It is calculated using the following formula:

r = Σ[(xi - x̄)(yi - ȳ)] / (√[Σ(xi - x̄)²] * √[Σ(yi - ȳ)²])

where xi and yi are the individual data points, x̄ and ȳ are the means of the two variables, and r is the correlation coefficient.

Q: What does a correlation coefficient of 1 mean?

A: A correlation coefficient of 1 means that there is a perfect positive linear relationship between the two variables. This means that as one variable increases, the other variable also increases.

Q: What does a correlation coefficient of -1 mean?

A: A correlation coefficient of -1 means that there is a perfect negative linear relationship between the two variables. This means that as one variable increases, the other variable decreases.

Q: What does a correlation coefficient of 0 mean?

A: A correlation coefficient of 0 means that there is no linear relationship between the two variables.

Q: How can I use this information to improve my writing skills?

A: By understanding the relationship between word count and essay scores, you can focus on producing high-quality essays within a limited timeframe. This means paying attention to grammar, syntax, and content, as well as meeting the word count requirements.

Q: Can I use this information to cheat on timed writing contests?

A: No, using this information to cheat on timed writing contests is not acceptable. The purpose of this study is to provide insights into the factors that contribute to a winning essay, not to help students cheat.

Q: How can I get more information about the study?

A: The data used in this study is available in the appendix. You can also contact the researcher, Ms. Sutton, for more information.

Q: Can I use this information for my own research?

A: Yes, you can use this information for your own research. However, please be sure to cite the original study and provide proper credit to the researcher.

In conclusion, the relationship between word count and essay scores is a complex one. By understanding the correlation coefficient and how it is calculated, you can gain valuable insights into the factors that contribute to a winning essay. Remember to use this information responsibly and to always follow the rules of timed writing contests.

Sutton, M. (2023). Timed Writing Contest Data. Unpublished dataset.

The data used in this study is available in the appendix.

Essay Rank	Word Count	Score
1	250	95
2	220	92
3	280	90
4	200	88
5	240	86
6	260	84
7	230	82
8	270	80
9	210	78
10	290	76

Essay Rank	Word Count	Score
1	250	95
2	220	92
3	280	90
4	200	88
5	240	86
6	260	84
7	230	82
8	270	80
9	210	78
10	290	76

Essay Rank	Word Count	Score
1	250	95
2	220	92
3	280	90
4	200	88
5	240	86
6	260	84
7	230	82
8	270	80
9	210	78
10	290	76

Essay Rank	Word Count	Score
1	250	95
2	220	92
3	280	90
4	200	88
5	240	86
6	260	84
7	230	82
8	270	80
9	210	78
10	290	76

Essay Rank	Word Count	Score
1	250	95
2	220	92
3	280	90
4	200	88
5	240	86
6	260	84
7	230	82
8	270	80
9	210	78
10	290	76

Essay Rank	Word Count	Score
1	250	95
2	220	92
3	280	90
4	200	88
5	240	86
6	260	84
7	230	82
8	270	80
9	210	78
10	290	76