Abstract
By using 30-day dietary records of 42 students living in a dormitory of a women's college, the variations in the intake of nutrients for the group of students were related to the varying length of time of survey; 1 day or consecutive 3, 5 or 7 days. For all the nutrients, the average nutrient intake per day per person showed the variation with a decreasing tendency by elongation of the length of time of survey, but the extent of decrease in the variation of the averages differed among nutrients, e. g., the largest decrease was observed for calcium and the smallest for fat.
The distance from the average obtained from 30-day records diminished to a less extent along with elongation of the length of time of survey.
Frequencies of cases when the 30-day average did not fall in the range of expected value calculated on the sample average and the sample variance by using t-statistic, became small for such nutrients as calcium, energy, protein, fat and iron, but unchanged substantially for vitamins.
The length of time to be studied was discussed in relation to pattern of variation and appropriate occasion.
