This question is asked here, and it also seems to be on everyone's mind with the "Muslim Radicalization Hearing".
So...when is something just an individual action, and when does it reflect on the values of the larger group?
1. It's hard to accurately paint a very large group with the same brush. For example, you've got hundreds of millions of Christians and hundreds of millions of Muslims, they are spread all over the globe and divided into different sects which occasionally go to war against each other, so any broad generalization isn't going to be helpful.
2. It's helpful to remember that the members of a group that you may see could represent a specific small subset of the overall group. For example, the Asians that I know represent the small subset that immigrated to the Toronto area, which means that they had the money and education to do so and the willingness to live in a western culture. Even more specifically, since my husband is a doctor, the ones that we know are often doctors that he works with or that he trained with. That doesn't mean that most Asians in the world are doctors - but it does mean that there are a fair number of Asian medical students at the University of Toronto.
3. Keep in mind that some disputes between different religious groups are based on specific religious teachings, but in others, religion is no more than the "team jersey" of the group where the real issue is land, political power, etc.
4. Look at whether a particular behavior is actually linked to an explicit teaching. For example, you would likely find Quakers, Mennonites and Jehovah's Witnesses to be under-represented in armies around the world, because these religions preach that members should not fight in wars, regardless of the issues involved.
5. Look at whether someone's behavior may have been linked to the teachings of a specific sect or leader, even if contrary teachings exist within the religion as a whole. So, some groups may frown on university education even if it is common among members of the religion as a whole. You can find this with any other issue as well. For example, I happened to come across a fair number of Orthodox "crunchy moms" when I was in the process of becoming more religious, so extended breastfeeding, babywearing, gentle discipline and general attachment parenting became part of my religious identity and I had books from rabbis to back up my views. It came as a bit of a shock when I found Orthodox Jews with opposite views, and discovered that they often followed different rabbis and different teachings. You can find this with other views as well. For example, while many religions have a version of the Golden Rule or Love Thy Neighbor, they don't all define who is included the same way. Does it apply to everything in the world, or only those of the same religion, or only those of the same religion who hold all the same views and do all the right things so that they aren't heretics or sinners?
6. Look at the impact of history and culture. Ruling religions developed differently from underdog religions. Some religions are tied into a specific geography and culture, some aren't.