Descriptive Statistics
Marcello Pagano, Kimberlee Gauvreau, Heather Mattie in Principles of Biostatistics, 2022
Cumulative frequency polygons can also be used to obtain the percentiles of a set of data. The 95th percentile is a value which is greater than or equal to 95% of the observations and less than or equal to the remaining 5%. Similarly, the 75 percentile is a value which is greater than or equal to 75% of the observations and less than or equal to the other 25%. This definition is only approximate because taking 75% of an integer does not typically result in another integer; consequently, there is often some rounding or interpolation involved. In Figure 2.6, the 50th percentile of the serum cholesterol levels for the group of 25- to 34-year-olds – the value that is greater than or equal to half of the observations and less than or equal to the other half – is approximately 193 mg/100 ml; the 50th percentile for the 55- to 64-year-olds is about 226 mg/100 ml.
Inequalities in global wealth distribution
Théodore H MacDonald, Noël A Kinsella, John A Gibson in The Global Human Right to Health, 2018
To understand percentile distributions, the reader has to be clear about the difference between a percentage and a percentile. A percentage is a fraction of 100. Thus 3% of, say, 51,650 is 3 × 516 + 3 × ½ = 1,549.5, because there are 516 hundreds in 51,600 and half of a hundred in 50. A percentile, on the other hand, refers to rankings, from 0% to 100% of the list of numbers from the lowest to the highest. For instance, it might be calculated that the income of the top 10-percentile is only slightly in excess of the bottom 40-percentile. Thus percentile refers to an ascending number scale of 100 equal divisions of a range of statistical data (e.g. incomes), that indicates the value below which any given percentage of the data lies. For example, if a person (or community) is at the 83rd percentile on the income range, this means that 17% of the population concerned is above that income.
Data Presentation
Marcello Pagano, Kimberlee Gauvreau in Principles of Biostatistics, 2018
Percentiles are useful for describing the shape of a distribution. For example, if the 40th and 60th percentiles of a set of data lie an equal distance away from the midpoint, and the same is true of the 30th and 70th percentiles, the 20th and 80th, and all other pairs of percentiles that sum to 100, the data are symmetric, that is, the distribution of values has the same shape on each side of the 50th percentile. Alternatively, if there are a number of outlying observations on one side of the midpoint only, the data are said to be skewed. If these observations are smaller than the rest of the values, the data are skewed to the left; if they are larger than the other measurements, the data are skewed to the right. The various shapes that a distribution of data can assume are discussed further in Chapter 3.
Improving work-related musculoskeletal disorders for sewing machine operators in Ethiopia
Published in International Journal of Occupational Safety and Ergonomics, 2023
Adbaru Esubalew Abate, Shalemu Sharew Hailemariam
Anthropometry is used to fit the worker in the workplace or to determine the matching of the existing facilities or equipment and the employee or workers. Generally, anthropometric measurements are expressed as a percentile measure used to represent the value below which a given percentage of observations fall. For example, the 95th percentile is the value below which 95% of the observations may be found [49]. For the improvement of the sewing workstation, 179 (11 male and 168 female) garment workers’ anthropometry measurements were taken. Anthropometry measurement standards were used to measure the dimensions of the existing sitting chair in standard sitting and standing positions. Worker body dimensions were measured when the worker was seated erect on a flat horizontal surface, their lower and upper legs were at right angles (knee bent at 90°) and their bare feet placed on the flat floor. Comparisons have been made between workers’ anthropometric measurements and the existing sitting chair dimensions. Mean and percentile values have been analyzed using Microsoft Excel 2016. The anthropometric measurement and sitting chair dimensions were then calculated for redesigning the operators’ sitting chair. The existing sitting chair dimensions in the case company are a seat height of 47 cm, seat depth of 44 cm and seat width of 32 cm.
Investigation of possible associations of the BDNF, SNAP-25 and SYN III genes with the neurocognitive measures: BDNF and SNAP-25 genes might be involved in attention domain, SYN III gene in executive function
Published in Nordic Journal of Psychiatry, 2022
Hilmi Bolat, Gül Ünsel-Bolat, Semiha Özgül, Erhan Parıltay, Akın Tahıllıoğlu, Luis Augusto Rohde, Haluk Akın, Eyüp Sabri Ercan
The CNS Vital Signs brief clinical evaluation battery consists of seven tests: verbal and visual memory, finger tapping, symbol digit coding, the Stroop Test, a test of shifting attention and the continuous performance test. The 7 tests generate 17 primary scores and 5 domain scores. These domain scores are memory (derived from verbal and visual memory), psychomotor speed (from finger tapping and symbol-digit coding), reaction time (Stroop test), cognitive flexibility (Stroop test and shifting attention test), and complex attention (Stroop test, shifting attention test, and continuous performance test). Domain scores are generated as raw scores and then computed as standard scores for age. Standard scores have a mean of 100 and a standard deviation of 15. A standard score of 100 represents the 50th percentile. For standard scores, higher is always better (e.g. a lower standard score in the reaction time domain represents a slower response). A Neurocognition Index (NCI) is also computed representing the mean of the 5 domains scores. We also presented, here, findings for the CPT scores separately. In this case, higher scores mean better performance for correct responses and taps. For errors and reaction times, lower scores are better (for more details on the tests, please see [30].
Establishment of the reference interval for high-sensitivity cardiac troponin T in healthy children of Chongqing Nan’an district
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2021
Qingfang Guo, Di Yang, Yan Zhou, Shuhua Zhang, Tao Zhu, Aihua Wang, Mingde Lei, Xuejing Yang
Bootstrap was used to extract datasets of equal sample size for each age group. The 99th, 97.5th, 95th, 90th, and 50th percentile values were calculated (99th%, 97.5th%, 95th%, 90th%, 50th%). This method was used to estimate the mean value of each quantile 100,000 times. The detailed results are shown in Table 3. In this paper, we estimate the statistics by sampling the original samples, combining with WS/T 402-2012 and CLSI C28-A3 standards and the ESC and ACC joint expert consensus in 2007 [27]. The upper limit of the reference interval was the 99th% of hs-cTnT concentration after bootstrap. This investigation shows that the concentration level of hs-cTnT in newborns (2–28 days) is the highest, and it gradually decreases with the increase of age and decreases to the adult reference range (0–14ng/L) at the age of one year or above, as shown in Table 3.
Related Knowledge Centers
- Body Weight
- Quantile
- Body Weight
- Sample Size Determination
- Quartile
- Percentile Rank
- Test Score
- Norm-Referenced Test
- Ranking
- Order Statistic
- Decile