Alissa Fong

**MA, Stanford University**

Teaching in the San Francisco Bay Area

Alissa is currently a teacher in the San Francisco Bay Area and Brightstorm users love her clear, concise explanations of tough concepts

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What I have here is the mean number of days that a person spent, mean number of minutes per day that a person spent on Facebook. On this day they spent 75 minutes that’s like a little more than an hour right? Because an hour would be 60 minutes. This day was like half an hour, 36 minutes, this day they never even got on Facebook, here was an hour and a half, that was like an hour. So you can see there is a range. It's like some days they spend more minutes than others. This day they never even got on the internet, maybe they were out of town or something.

Anyway we’ve got to find the mean. This is the key word mean. Remember the way to find mean is to add up all your values and then divide by how many they have. So grab a calculator. What I’m going to do is go in there and type in all of these numbers, add them up all together and you get 261. I did that before hand I kind of cheated. Once you add all of those you get 261 and we need to divide by how many values we have 1, 2, 3, 4, 5. This data set represents 5 days on the computer.

When you do that you see y our answer is 52.2 minutes. This person spends less than hour per day on Facebook, so if their parents were given them a hard time, they could say hey guys it’s less than an hour give me a break here because there are some days where this person is not at all. There’s other days where they’re on for an hour and a half, but usually it’s less than an hour.

Mean is a good way to describe usually. Usually I’m on Facebook for less than an hour. Again you add up all these numbers and then divide by 1, 2, 3, 4, 5, because we have 5 values.