This is my first time trying an argument task in GRE. I need some comments. I would be very appreciated!

question:
The following appeared in a memorandum from the Director of the Human Resources to the executive officers of Company X.
"Last year, we surveyed our employees on improvements needed at Company X by having them rank, in order of importance, the issues presented on a list of possible improvements. Improved communications between employees and management was consistently ranked as the issue of highest importance by the employees who responded to the survey. As you know, we have since instituted regular communications sessions conducted by high-level management, which the employees can attend on a voluntary basis. Therefore, it is likely that most employees at Company X now feel that the improvement most needed at the company has been made."
Write a response in which you discuss what questions would need to be answered in order to decide whether the recommendation and the argument on which it is based are reasonable. Be sure to explain how the answers to these questions would help to evaluate the recommendation.


In this memorandum, the author recommends that employees at Dexter Gorman Instruments should complete their work during the regular 40-hour work week and only work overtime when there is an emergency. To support this recommendation, the author quotes an internal study conducted in the company, which indicates that employees across several divisions who worked 48 or more on average per week tend to make more work errors than their fellow employees. This looks convincing at the first glance, but there are several questions with regards to the author’s lines of reasoning that require further analysis. The argument could end up being quite convincing, or invalid in the end.
To start with, the author’s recommendation relies heavily on this internal study, which has not been proven to be reliable and to be able to generate statistically significant conclusions. It did not mention the number of employees involved in this study, which can be also viewed as the sample size. The number of individuals in a study must reach a certain number to generate statistically meaningful results, otherwise, the conclusion derived from a study is not reliable at all. There might only be four or five employees in this study, and coincidently, they made more errors than others. It would be unreasonable to apply this “incidental” result from a small sample group to a general case. Moreover, the candidates in the study were chosen by the managers, which might bring some potential errors into this study. The managers are obviously occupied by various issues at work, so they might not be aware of the working hours of each employee in their divisions. Therefore, the validity of this study might seriously challenge the author’s suggestion or strengthen the author’s suggestion once it is answered.
The second question that I would like to ask is the reliability of the so-called “documented work errors”. The author made his/her claim based on the number of documented work errors. This conclusion relies on the assumption that all errors at work were documented, and no errors were missed. There is no guarantee that the employees would report all their work errors, and all the work errors were found by them. Therefore, whether the documented work errors were the total errors needs to be verified to support the author’s claim.
Moreover, we need to consider the reason behind the larger number of work errors by the employees who worked overtime. Employees who worked overtime might complete a much larger amount of work than those who did not, which naturally might lead to a larger number of work errors. Intuitively, more work, more errors; less work, fewer errors. Yet, if the author can provide more information about the work amount and work error, his/her suggestion might still be reasonable.
To sum up, there are still several questions that need to be answered so that the author’s recommendation can be tenable. Only after those questions are adequately addressed can we effectively evaluate the author’s argument and reach a logically sound conclusion.