Homework 2

Part 1


When will app downloads on the iPhone surpass music downloads?

There are 12 million songs on iTunes, but only 250,000 apps. However, Apps have reached 7 billion downloads in 2.2 years, whereas it took 5 years for music to reach this level. Fortune predicts that this could happen by the end of the year. Nowadays people are more apt to customize their phones with apps, whereas in the past it was with ringtones from music downloaded. Also, many of the apps are free, but you have to pay for most music. Both are easily accessible, but with the price difference it is easy to see how app downloads have grown so quickly.

I personally think that since there are simply many more songs available, it won’t be until sometime next year that this will happen. However, it would not be hard to believe that some people would think it would take even longer. Then again, an optimistic group could follow the rising growth and come up with an estimate that this will occur before year’s end. By applying the Delphi method, we can eliminate the two extremes and average the middle. This would cut out this years estimate as well as the estimate for late next year. This would leave my estimate of early next year. This is absolutely theoretically possible and I do not see any risks or possibilities that would prevent it from occurring.


Part 2

Estimate the doubling time of the software development productivity of the average programmer, if productivity increases at 6%/year.

Using the equation .06x=1 (.06 being 6%, x being the amount of years, and 1 being a 100% increase, or a doubling), it would take 16 2/3 or 16.66667 years.


Estimate the percent per year of increase in the complexity of PCs if this complexity doubles every 2 years.

Using the equation 2x=1, solve for x, x=.5 or 50%.


Estimate the percent per year of increases in the complexity of PCs if complexity doubles every 18 months, as some think it is doing.

Using the equation 1.5x=1, this would mean a 2/3 increase or .66667%/year.


What is the doubling time of your money if you have it in the bank making 2% interest per year?

Using the equation .02x=1, it would take 50 years for your money to double.