Vitamin B12 is an essential coenzyme. It plays a key role in neurological function and red blood cell development. Vitamin B12 deficiency can present with a wide variety of symptoms, including fatigue, dizziness, mood changes, and disturbed vision. As Vitamin B12 is found almost exclusively in animal-based food sources, plant-based diets can result in deficiency. Therefore, it is important for people who follow plant-based diets to regularly check their Vitamin B12 levels. A recent study showed that the requirement for fasting prior to the Vitamin B12 blood test was not standardised across clinical sites. The researchers were concerned that the observed Vitamin B12 levels would be higher in non-fasted individuals than fasted individuals.

To determine whether observed mean blood Vitamin B12 levels are elevated in a non-fasting state compared to a fasting state, the researchers recruited 20 participants. Each of the participants had their Vitamin B12 levels checked twice. On Day 1, Vitamin B12 levels were measured after fasting for 8 hours. On Day 2, Vitamin B12 levels were measured without prior fasting. Answer this research question using the 1% level of significance.

Participant VitB12 Fasting (pg/ml) VitB12 Non-fasting (pg/ml) Person_1 488 568 Person_2 605 596 Person_3 656 739 Person_4 572 686 Person 5 457 588 Person_6 537 549 Person_7 468 533 Person 8 436 333 Person 9 424 406 Person_10 583 714: Person_11 558 590 Person 12 588 545 Person 13 638 672 Person_14 560 531 Person_15 681 626 Person 16 610 649 Person_17 504 542 Person_18 582 478 Person_19 418 626 Person 20 519 605