Data Analysis isn’t really about statistics. It’s about looking at data, reaching a conclusion based on what the data shows, and presenting it to an audience.
Most people have a negative opinion about statistics, but statistics are just a tool for presenting data. Used correctly, they paint an accurate picture of the way things are in a way that is far more clear and concise than showing every single measurement and data point. Used incorrectly–either purposefully, or through ignorance–they can distort and falsify reality.
Be conscious of what it is you’re trying to show. If the data doesn’t support your theory, it’s wrong to manipulate it so that it does. But even if the data does seem to match, you have to consider whether or not the way you present it is making the result clear to the audience.
Don’t show how you got to the numbers in your presentation. Someone will find fault with them and derail the discussion. That said, make the underlying data available–after the presentation.
In fact, avoid throwing lots of numbers at people. Graphical representations get your point across with greater clarity.
Phone numbers are 7 digits long because that’s the number of discrete things people can keep in their heads at one time: 7 plus or minus 2. Keep a single slide of your presentation to about 7 bullet points.
Remember that some people are colorblind when you choose colors for your graphs.
Offering an opinion without having data to back it up is just asking for someone to doubt you. If you want to win your argument, get to the numbers.