A comparison of two estimates of standard error for a ratio-of-means estimator for a mapped-plot sample design in southeast Alaska.

Deforestation is the direct human-induced conversion of forest to nonforest land uses. It is important for nations to understand and report the extent of their deforestation. Because of the vastness of Canada’s forest and the rare and spatially diverse nature of its deforestation, a sampling approach in which deforestation is mapped and then scaled up to represent deforestation for different regions was needed. The effectiveness of different sample designs in capturing the area of deforestation was evaluated using a Monte Carlo approach in which alternate sample designs were applied to simulated forest landscapes representative of different regions and deforestation patterns in Canada. Sampling error as expressed by the standard error in the estimated deforestation level for the sample divided by actual deforestation of the simulated landscape was used as a measure of sample design performance. Results indicated that sampling error was dependent on the characteristics of the deforestation (e.g., amount, shape, size, and distribution). For example, as mean event size increases or the proportion of linear deforestation events (e.g., roads and corridors) decreases, the required sampling intensity to reach a certain level of sampling error increases, and landscapes with a small number of very large events required the largest sampling intensity. To achieve a relative sampling error target (standard error / sample mean) of 10%, given sample designs of square plots on a systematic grid, a sample of 15%–25% of a landscape will be required for most Canadian landscapes, given a 10-year mapping time frame (interval between samples) and assuming a deforestation rate of 0.025% per annum. With mapping over a 5-year period, the required sampling intensity rises to 20%–40%. Also discussed are the consequences of the sampling error of different designs on the uncertainty in estimated greenhouse gas emission resulting from deforestation.

Download Full-text

The combined Herstmonceux Cambridge Program of optical positions of radio sources

International Astronomical Union Colloquium ◽

10.1017/s025292110007408x ◽

1978 ◽

Vol 48 ◽

pp. 155-166 ◽

Cited By ~ 1

Author(s):

A. N. Argue ◽

E. D. Clements ◽

G. M. Harvey ◽

C. A. Murray

Keyword(s):

Standard Error ◽

Unit Weight ◽

Radio Sources

SummaryAGK3-based optical positions are presented for 38 counterparts of radio sources selected from the catalogue of Elsmore & Ryle. The measurements were made from plates taken with the 13-inch Astrograph, the 26-inch refractor and the 2.5 m (INT) reflector at Herstmonceux, and the 17-inch Schmidt at Cambridge. The standard error for a mean position of unit weight is 0”.11, and the weights range from 3.0 for the brightest sources to 0.5 for the faintest. Comparison with the radio positions shows no significant differences. The effects of applying the Brorfelde corrections to AGK3 are discussed.

Download Full-text

Multi-Center Calibration of the Second Reference Material for Thromboplastin, Rabbit, Plain, Coded CRM 149R

Thrombosis and Haemostasis ◽

10.1055/s-0038-1648132 ◽

1991 ◽

Vol 65 (03) ◽

pp. 263-267 ◽

Cited By ~ 3

Author(s):

A M H P van den Besselaar ◽

R M Bertina

Keyword(s):

Reference Material ◽

Standard Error ◽

Standard Errors ◽

Sensitivity Index ◽

Long Term Stability ◽

Significant Bias ◽

The Mean ◽

The Relationship ◽

International Sensitivity Index

SummaryIn a collaborative trial of eleven laboratories which was performed mainly within the framework of the European Community Bureau of Reference (BCR), a second reference material for thromboplastin, rabbit, plain, was calibrated against its predecessor RBT/79. This second reference material (coded CRM 149R) has a mean International Sensitivity Index (ISI) of 1.343 with a standard error of the mean of 0.035. The standard error of the ISI was determined by combination of the standard errors of the ISI of RBT/79 and the slope of the calibration line in this trial.The BCR reference material for thromboplastin, human, plain (coded BCT/099) was also included in this trial for assessment of the long-term stability of the relationship with RBT/79. The results indicated that this relationship has not changed over a period of 8 years. The interlaboratory variation of the slope of the relationship between CRM 149R and RBT/79 was significantly lower than the variation of the slope of the relationship between BCT/099 and RBT/79. In addition to the manual technique, a semi-automatic coagulometer according to Schnitger & Gross was used to determine prothrombin times with CRM 149R. The mean ISI of CRM 149R was not affected by replacement of the manual technique by this particular coagulometer.Two lyophilized plasmas were included in this trial. The mean slope of relationship between RBT/79 and CRM 149R based on the two lyophilized plasmas was the same as the corresponding slope based on fresh plasmas. Tlowever, the mean slope of relationship between RBT/79 and BCT/099 based on the two lyophilized plasmas was 4.9% higher than the mean slope based on fresh plasmas. Thus, the use of these lyophilized plasmas induced a small but significant bias in the slope of relationship between these thromboplastins of different species.

Download Full-text

Stephen T. Ziliak and Deirdre N. McCloskey's The cult of statistical significance: how the standard error costs us jobs, justice, and lives. Ann Arbor (MI): The University of Michigan Press, 2008, xxiii+322 pp.

Erasmus Journal for Philosophy and Economics ◽

10.23941/ejpe.v1i1.12 ◽

2008 ◽

Vol 1 (1) ◽

pp. 154 ◽

Cited By ~ 8

Author(s):

Aris Spanos

Keyword(s):

Standard Error ◽

Statistical Significance ◽

University Of Michigan ◽

Ann Arbor ◽

The University ◽

Error Costs

Download Full-text

PENILAIAN KESEHATAN TERUMBU KARANG MENGGUNAKAN CITRA SATELIT WORLDVIEW-2 DI PULAU PAHAWANG, LAMPUNG, INDONESIA

Seminar Nasional Geomatika ◽

10.24895/sng.2017.2-0.405 ◽

2018 ◽

Vol 2 ◽

pp. 125

Author(s):

Lukman Hakim

Keyword(s):

Error Estimation ◽

Standard Error ◽

Red Edge ◽

Standard Error Estimation

Perairan laut Lampung sebagai bagian kecil dari ekosistem terumbu karang Indonesia terindikasi memiliki tren penurunan kualitas karena aktivitas pelayaran dan pariwisata yang ekstensif khususnya di Pulau Pahawang. Kontrol kondisi terumbu karang pada wilayah ini menjadi kegiatan vital dalam rangkaian konservasi sumber daya laut. Sayangnya, pemetaan kesehatan terumbu karang memerlukan survei detail yang memakan banyak waktu, biaya, dan tenaga. Citra sebagai produk data penginderaan jauh hadir sebagai solusi monitoring terumbu karang secara cepat, murah, dan dalam jangkauan wilayah yang relatif luas. Tujuan dari penelitian ini adalah untuk memetakan kesehatan terumbu karang melalui citra WorldView-2 (WV-2) serta menguji akurasi peta yang dihasilkan. Metode yang digunakan untuk memetakan kesehatan terumbu karang adalah transformasi nilai pixel pada band-band WV-2 menjadi nilai original objek dengan urutan: 1) koreksi atmosfer (Top of Atmospheric Reflectance), 2) koreksi kilap air (sun glint), dan 3) koreksi kolom air (metode lyzenga) menghasilkan 15 band DII (depth invariant bottom index). Kelima belas band DII tersebut diubah menjadi nilai kesehatan terumbu karang dengan cara regresi antara nilai pixel pada band DII dengan nilai rasio kesehatan terumbu karang aktual yang diperoleh dari proses kalkulasi acak titik foto transek di lapangan. Tiga tipe regresi (linier, eksponen, dan polinomial) dilakukan untuk melihat persamaan terbaik yang bisa digunakan untuk mentransformasi nilai pixel ke nilai kesehatan terumbu karang. Persamaan terbaik kemudian diimplementasikan menjadi model kesehatan terumbu karang untuk kemudian diuji akurasi menggunakan metode Standard Error Estimation. Hasil terbaik diperoleh pada regresi antara rasio kesehatan terumbu karang dengan band DII Coastal Red-Edge dengan koefisien determinasi (R2) sebesar 0,6553 dan akurasi pemetaan sebesar 70,191%. Nilai tersebut menunjukan bahwa citra WV-2 memiliki potensi untuk menjadi instrumen monitoring ekosistem marine yang layak.Kata Kunci: Depth Invariant Bottom Index, Kesehatan Terumbu Karang, Lyzenga, Regresi, WorldView-2

Download Full-text