This has become quite a frustrating question, but I've asked in the Coursera discussions and they won't help. Below is the question:

I've gotten it wrong 6 times now. How do I normalize the feature? Hints are all I'm asking for.

I'm assuming x_2^(2) is the value 5184 unless I am adding the x_0 column of 1's, which they don't mention but he certainly mentions in the lectures when talking about creating the design matrix X. In which case, x_2^(2) would be the value 72. Assuming one or the other is right (I'm playing a guessing game), what should I use to normalize it? He talks about 3 different ways to normalize in the lectures: one using the maximum value, another with the range/difference between max and mins, and another the standard deviation -- they want an answer correct to the hundredths. Which one am I to use? This is so confusing.