Final answer:
Psychologists are required to maintain records for a specified number of years, which varies. To practice professionally, psychologists usually need a doctoral degree in psychology. The IRS topic mentioning Form 1040 and a statistical sample is unrelated to psychologists' record-keeping.
Step-by-step explanation:
The length of time a psychologist must keep complete records is not directly stated within the given passage. However, in a broader context, psychologists are generally required to maintain records for a certain number of years as specified by legal, regulatory, ethical, and other considerations, which can vary by jurisdiction and the type of record. An individual working towards a doctoral degree in psychology must understand these regulations as part of their professional practice.
In unrelated information regarding the Internal Revenue Service (IRS) records, individuals are noted to spend an average of 10.53 hours on IRS Form 1040. For the statistical question about the random sample of 36 taxpayers, the symbol X would represent the average time it takes for the sampled group of taxpayers to complete the form, assuming the given mean time of 10.53 hours and standard deviation of two hours.