IQ and Probability of Success in Two Difficult Fields I've had my IQ measured on multiple tests over the past several decades. The first time was in middle school and it was measured at 120. I guarantee you that I didn't care about the result when I took that test as a kid. I probably wanted to get it over with. Much later in life, and consistent with another time later in life, my IQ was measured at 138. I am a believer that these measurements can vary with motivation, health, alertness, sleep deprivation, and other psychophysiological factors.

Based on my measured IQ range of 120-138, I'd like to see an answer to the following questions:

What is the probability that I could complete a PhD in Mathematics or Physics? What is the probability that I could contribute at least slightly significantly to either of those fields over the long term as a PhD?

One of my "best" qualities is that I'm very tenacious regarding problem-solving. I might not get there the quickest, but I don't give up until I do or the pursuit begins to interfere with other aspects of life. People might accuse me of being physically lazy, but there's no way they can accuse me of being problem-solving lazy. I'm the kind of person who will hire a home maintenance technician as a last resort only because I don't have the tools. I'm pretty frugal.

I feel pretty inferior to many of the people who have posted comments on StackExchange.
IQ is a terrible test for anything but certain types of pattern matching and to aid in educational intervention, and its limitations are well understood by actual psychological practitioners.  There are correlations, but the correlations are pretty loose.  With all those caveats, according to Wikipedia, you are totally in a reasonable range to get a Ph.D..