4.) (Portfolio) According to your results, does App Inventor's PRNG provide a good model of randomness?
According to the results, yes. Though it is not completely random, the percentages all hover roughly around 50% and do not deviate in one specific direction often enough to disregard its use as a suitable PRNG.
5.) (Portfolio) A friend claims that flipping a coin 100 times and finding that it comes up heads only 45% of the time shows that the coin is biased. How should you reply?
Flipping a coin 100 times is not a good test of whether or not a coin flip is biased. It cannot be definitively stated that because out of 100, 45 were heads but variance is expected when flipping a completely random event.