求助句型

明天的未来UID：2484785

那位高手可以帮忙看一下下面三组句型那个是正确的或者比较好，谢谢！

第一组

要表达“如果调查范围不正确或调查样本很小，结果都不可靠”
If the survey scope is wrong or the sample size is too small, the result of the survey would be unreliable.
If the survey scope is wrong or if the sample size is too small, the result of the survey would be unreliable.
No matter whether the survey scope is wrong or the sample size is too small, the result of the survey would be unreliable. 哪个正确

第二组
哪个正确，哪个比较好（主要看一下possible 后面的并列结构用or 好还是and 好 还是只能用and，同时并列结构后面需不需要加that）
It is entirely possible that most of the majors offered by Omega University are not market-oriented or this university does establish a thorough system of career guidance for its students.
It is entirely possible that most of the majors offered by Omega University are not market-oriented or that this university does establish a thorough system of career guidance for its students.
It is entirely possible that most of the majors offered by Omega University are not market-oriented and this university does establish a thorough system of career guidance for its students.
It is entirely possible that most of the majors offered by Omega University are not market-oriented and that this university does establish a thorough system of career guidance for its students.

第三组


哪个正确，哪个比较好 （同第二组的问题外，外加一个问题这里是thereby 好还是therefore 好，还是只能用一个，或者两个都不能用）
It is entirely possible that the school leaders pay much attention to music course and the school band, and thereby the school invests a lot of fund on them
It is entirely possible that the school leaders pay much attention to music course and the school band, and therefore/thus the school invests a lot of fund on them

狐狸大叔UID：2342950

If the survey scope is wrong or the sample size is too small, the result of the survey would be unreliable.

It is entirely possible that most of the majors offered by Omega University are not market-oriented and this university does establish a thorough system of career guidance for its students.

明天的未来UID：2484785

谢谢！