Q: I want to buy the fourth-generation iPod touch, but I have a few questions. I’ve noticed that the iPod touch battery life for video playback is 7 hours, and for audio it’s 40 hours. What is its battery life for continuous game playing and apps? Also, what is the average size of an app in the apps store and what is the percentage of free apps?

– Sunil

A: There are no standard answers to any of these questions since apps vary in size and performance. High-resolution, fast-paced action games that use the accelerometer and gyroscope and play a lot of audio are going to be a greater drain on the battery than simple puzzle games that only use the touchscreen. Further, a number of other factors will affect your battery life in any app such as how bright you keep the display whether you have Wi-Fi and Bluetooth enabled or disabled. With seven hours of video playback, it’s a safe bet that you’ll get close to that for typical gaming purposes, but your mileage may vary greatly depending on the types of games you’re playing.

Applications also vary greatly in size depending on their complexity and the amount of data storage required. Many of the more sophisticated games are in the 100-200MB range, with a few even as large as 500MB. Simpler puzzle games are generally smaller at around 20-50MB each. GPS navigation apps tend to be the largest due to the map data included with these apps, coming in around the 1.5-2GB range. Again, this is one of these situations where the size of apps will depend entirely on what types of apps you plan to use.

In terms of free apps, recent reports from third-party analytics firms suggest that around 28-33% of the apps on the App Store are free, however the average price of a paid app on the App Store tends to be in the $2-$4 range, with a large number of apps priced at $1. The vast majority of iPhone and iPod touch apps tend to be $10 or less, including even some of the best and top-rated games for the platform. The relatively few apps that sell for more than $10 are mostly professional and business applications.