![]() Therefore, it is important to consider the sample size while estimating the standard error in measurement. The standard error in measuring a longer length with the same precision decreases as the sample size increases. Therefore, the standard error of measuring 1.08 km with a precision of ± 0.01 m is 0.000833 m. ![]() Standard error = Standard deviation / √Sample size Standard deviation = 0.01 m / 2 = 0.005 m Standard deviation can be calculated as half of the precision as it is given as ± 0.01 m. ![]() The standard error is the standard deviation of the sample divided by the square root of the sample size. Sample size = Total length / Length that can be measured with precision We can determine the sample size by dividing the total length to be measured by the length that can be measured with precision. This means that the tape changes length by 1.16 mm per 10 m tape per 10 C change from the standard temperature of the tape. We need to convert 1.08 km to meters as the precision of measurement is given in meters. For common tape measurements, the tape used is a steel tape with coefficient of thermal expansion C equal to 0.000,011,6 units per unit length per degree Celsius change. We need to find the standard error in measuring 1.08 km with the same precision. Limiting the number of examiners, especially for waist circumference measurements, would yield a higher degree of reliability and validity.Given, the length that can be taped with a precision of ± 0.01 m is 30 m. There are 5 types of tapes available in surveying for linear measurements and they are as follows : Linen Tape. The findings of this study suggest that weight, height and waist circumference measured in adults aged 18 years and above, using the respective above mentioned instruments, are reliable and valid for use in a community survey. The technical error of measurement and coefficient of variation of weight and height for both inter-examiner and intra-examiner measurements were all within acceptable limits (below five percent). The height measurement, on average, using the test instrument, reported a recording of 0.4 cm higher than the reference instrument, with the upper and lower limits at 2.5 cm and 1.6 cm, respectively. The main causes of errors in the use of steel tape measure are as follows: a. The intra-examiner reliability in descending order was weight and height followed by waist circumference. ![]() The waist circumference was measured using the Seca circumference measuring tape S 201, to the nearest 0.1 cm. The height was measured using the Seca Bodymeter 206 and Stadiometer, both to the nearest 0.1 cm. The weight was measured using the Tanita HD-318 digital weighing scale to the nearest 0.1 kg, and Seca Beam Scale to the nearest 0.01 kg. Two public health nurses, trained to follow a standard protocol, obtained the weight, height and waist circumference measurements. This study aimed to assess the inter- and intra-examiner reliability, the technical error of measurement and the validity of instruments for measuring weight, height and waist circumference.Ī convenience sample of 130 adults working in a selected office setting was chosen to participate in the study, subject to the inclusion and exclusion study criteria. They are very similar to a standard encased tape, featuring a metallic hook to be anchored to the starting point of measurement. The Third National Health and Morbidity Survey Malaysia 2006 includes a nutritional status assessment of children.
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