The phrase "a portion of test" is not correct in English.
It should be "a portion of the test." You can use it when referring to a specific part or segment of a test or examination.
Example: "During the exam, I found that a portion of the test was particularly challenging."
Alternatives: "a part of the test" or "a segment of the test."
For sure, empirically there may be a portion of test-takers who simply rush through the test without any strategic reflection about their probability of success.
Tom Ewing, a spokesman for the testing service, which is responsible for security issues involving the College Board's college admissions exam, said an investigation had shown that an unknown number of students had seen at least a portion of the test before the exam was given on Jan . 27
"What they do is collect the motorists' fees and they pay a portion of the test fee for the equipment, training and management".
A specimen was considered to be a mixed failure when a portion of the test surfaces exposed and others had increments of retained resins.
Because each student responded to only a portion of the test items, a multiple imputation technique was used to create five sets of plausible values of reading scores for the whole sample (Foy et al. [2007]).
The variable was measured by Brunstrom (2011) using psychophysical methods: essentially a standard food of known energy content appears on a screen and the size of a portion of a test food is manipulated until it is estimated to make you feel equally full or alternatively will stave off hunger equally well.
A way to improve cost-effectiveness is to maximise the number of analytes that may be determined by a single procedure or from a single portion of test material, and/or to limit the sample pre-treatment steps.
I would never do the whole thing at once; I would always do a portion of it to test it out and make sure it was ok.
