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An operational definition of a statistically meaningful trend
Linear trend analysis of time series is standard procedure in many scientific disciplines. If the number of data is large, a trend may be statistically significant even if data are scattered far from the trend line. This study introduces and tests a quality criterion for time trends referred to as s...
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Published in: | PloS one 2011-04, Vol.6 (4), p.e19241 |
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description | Linear trend analysis of time series is standard procedure in many scientific disciplines. If the number of data is large, a trend may be statistically significant even if data are scattered far from the trend line. This study introduces and tests a quality criterion for time trends referred to as statistical meaningfulness, which is a stricter quality criterion for trends than high statistical significance. The time series is divided into intervals and interval mean values are calculated. Thereafter, r(2) and p values are calculated from regressions concerning time and interval mean values. If r(2) ≥ 0.65 at p ≤ 0.05 in any of these regressions, then the trend is regarded as statistically meaningful. Out of ten investigated time series from different scientific disciplines, five displayed statistically meaningful trends. A Microsoft Excel application (add-in) was developed which can perform statistical meaningfulness tests and which may increase the operationality of the test. The presented method for distinguishing statistically meaningful trends should be reasonably uncomplicated for researchers with basic statistics skills and may thus be useful for determining which trends are worth analysing further, for instance with respect to causal factors. The method can also be used for determining which segments of a time trend may be particularly worthwhile to focus on. |
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If the number of data is large, a trend may be statistically significant even if data are scattered far from the trend line. This study introduces and tests a quality criterion for time trends referred to as statistical meaningfulness, which is a stricter quality criterion for trends than high statistical significance. The time series is divided into intervals and interval mean values are calculated. Thereafter, r(2) and p values are calculated from regressions concerning time and interval mean values. If r(2) ≥ 0.65 at p ≤ 0.05 in any of these regressions, then the trend is regarded as statistically meaningful. Out of ten investigated time series from different scientific disciplines, five displayed statistically meaningful trends. A Microsoft Excel application (add-in) was developed which can perform statistical meaningfulness tests and which may increase the operationality of the test. The presented method for distinguishing statistically meaningful trends should be reasonably uncomplicated for researchers with basic statistics skills and may thus be useful for determining which trends are worth analysing further, for instance with respect to causal factors. The method can also be used for determining which segments of a time trend may be particularly worthwhile to focus on.</description><identifier>ISSN: 1932-6203</identifier><identifier>EISSN: 1932-6203</identifier><identifier>DOI: 10.1371/journal.pone.0019241</identifier><identifier>PMID: 21552532</identifier><language>eng</language><publisher>United States: Public Library of Science</publisher><subject>Alzheimer's disease ; Alzheimers disease ; Analysis ; Chlorophyll ; Climate Change - statistics & numerical data ; Criteria ; Data processing ; Earth science ; Earth sciences ; Geovetenskap ; Gross Domestic Product - trends ; Hypotheses ; Hypothesis testing ; Mathematical analysis ; Mathematics ; Methods ; Models, Statistical ; NATURAL SCIENCES ; NATURVETENSKAP ; Nitrogen ; Phosphorus ; Probability ; Regression analysis ; Significance ; Software ; Spreadsheet software ; Statistical analysis ; Statistical significance ; Statistics ; Statistik ; Time series ; trend ; Trend analysis ; trendanalys ; Trends</subject><ispartof>PloS one, 2011-04, Vol.6 (4), p.e19241</ispartof><rights>COPYRIGHT 2011 Public Library of Science</rights><rights>2011 Bryhn, Dimberg. 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If the number of data is large, a trend may be statistically significant even if data are scattered far from the trend line. This study introduces and tests a quality criterion for time trends referred to as statistical meaningfulness, which is a stricter quality criterion for trends than high statistical significance. The time series is divided into intervals and interval mean values are calculated. Thereafter, r(2) and p values are calculated from regressions concerning time and interval mean values. If r(2) ≥ 0.65 at p ≤ 0.05 in any of these regressions, then the trend is regarded as statistically meaningful. Out of ten investigated time series from different scientific disciplines, five displayed statistically meaningful trends. A Microsoft Excel application (add-in) was developed which can perform statistical meaningfulness tests and which may increase the operationality of the test. 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The method can also be used for determining which segments of a time trend may be particularly worthwhile to focus on.</description><subject>Alzheimer's disease</subject><subject>Alzheimers disease</subject><subject>Analysis</subject><subject>Chlorophyll</subject><subject>Climate Change - statistics & numerical data</subject><subject>Criteria</subject><subject>Data processing</subject><subject>Earth science</subject><subject>Earth sciences</subject><subject>Geovetenskap</subject><subject>Gross Domestic Product - trends</subject><subject>Hypotheses</subject><subject>Hypothesis testing</subject><subject>Mathematical analysis</subject><subject>Mathematics</subject><subject>Methods</subject><subject>Models, Statistical</subject><subject>NATURAL SCIENCES</subject><subject>NATURVETENSKAP</subject><subject>Nitrogen</subject><subject>Phosphorus</subject><subject>Probability</subject><subject>Regression analysis</subject><subject>Significance</subject><subject>Software</subject><subject>Spreadsheet software</subject><subject>Statistical analysis</subject><subject>Statistical significance</subject><subject>Statistics</subject><subject>Statistik</subject><subject>Time series</subject><subject>trend</subject><subject>Trend analysis</subject><subject>trendanalys</subject><subject>Trends</subject><issn>1932-6203</issn><issn>1932-6203</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2011</creationdate><recordtype>article</recordtype><sourceid>PIMPY</sourceid><sourceid>DOA</sourceid><recordid>eNqNkm2L1DAQx4so3nn6DUQLgiC4ax6aNn2hsJx3unBw4MO9DWky6WbpNjVp1fv2pru9YwsKNi_azPzm35nhnyTPMVpiWuB3Wzf4VjbLzrWwRAiXJMMPklNcUrLICaIPj75PkichbBFilOf54-SEYMYIo-Q0eb9qU9eBl711US3VYGxrx0vqTCrT0MdM6K2STXOb7kC2tq3N0KS9h1Y_TR4Z2QR4Nr3Pku-XF9_OPy-urj-tz1dXC1UQ3i-KAkElKWBTVgyQwZJwQplShJsCcMVQkXNaVoRjGlOFRPHhMUhUDFQ5PUteHnS7xgUxTR4EJiUvCSkKFon1gdBObkXn7U76W-GkFfuA87WQPo7RgDAaje1IKjOdYQ4SQ1lprVWVMZ3v__b2oBV-QTdUM7WP9ma1VxsGgVnsdcQ_TM0N1Q60grb3splVzTOt3Yja_RQU8YxwFAVeTQLe_Rgg9P-YcKJqGYewrXFRTO1sUGKVxf2VJGc8Usu_UPFo2FkVrWJsjM8K3swKItPD776WQwhi_fXL_7PXN3P29RG7Adn0m-CaYbRWmIPZAVTeheDB3G8OIzE6_W4bYnS6mJwey14cb_2-6M7a9A_pefjb</recordid><startdate>20110428</startdate><enddate>20110428</enddate><creator>Bryhn, Andreas C</creator><creator>Dimberg, Peter H</creator><general>Public Library of Science</general><general>Public Library of Science (PLoS)</general><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>IOV</scope><scope>ISR</scope><scope>3V.</scope><scope>7QG</scope><scope>7QL</scope><scope>7QO</scope><scope>7RV</scope><scope>7SN</scope><scope>7SS</scope><scope>7T5</scope><scope>7TG</scope><scope>7TM</scope><scope>7U9</scope><scope>7X2</scope><scope>7X7</scope><scope>7XB</scope><scope>88E</scope><scope>8AO</scope><scope>8C1</scope><scope>8FD</scope><scope>8FE</scope><scope>8FG</scope><scope>8FH</scope><scope>8FI</scope><scope>8FJ</scope><scope>8FK</scope><scope>ABJCF</scope><scope>ABUWG</scope><scope>AFKRA</scope><scope>ARAPS</scope><scope>ATCPS</scope><scope>AZQEC</scope><scope>BBNVY</scope><scope>BENPR</scope><scope>BGLVJ</scope><scope>BHPHI</scope><scope>C1K</scope><scope>CCPQU</scope><scope>D1I</scope><scope>DWQXO</scope><scope>FR3</scope><scope>FYUFA</scope><scope>GHDGH</scope><scope>GNUQQ</scope><scope>H94</scope><scope>HCIFZ</scope><scope>K9.</scope><scope>KB.</scope><scope>KB0</scope><scope>KL.</scope><scope>L6V</scope><scope>LK8</scope><scope>M0K</scope><scope>M0S</scope><scope>M1P</scope><scope>M7N</scope><scope>M7P</scope><scope>M7S</scope><scope>NAPCQ</scope><scope>P5Z</scope><scope>P62</scope><scope>P64</scope><scope>PATMY</scope><scope>PDBOC</scope><scope>PIMPY</scope><scope>PQEST</scope><scope>PQQKQ</scope><scope>PQUKI</scope><scope>PRINS</scope><scope>PTHSS</scope><scope>PYCSY</scope><scope>RC3</scope><scope>5PM</scope><scope>ACNBI</scope><scope>ADTPV</scope><scope>AOWAS</scope><scope>D8T</scope><scope>DF2</scope><scope>ZZAVC</scope><scope>DOA</scope></search><sort><creationdate>20110428</creationdate><title>An operational definition of a statistically meaningful trend</title><author>Bryhn, Andreas C ; Dimberg, Peter H</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c728t-770eba3e1f9b5e0f1a28235cc28f7e1b5076839b2813a287a000080762c13ab63</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2011</creationdate><topic>Alzheimer's disease</topic><topic>Alzheimers disease</topic><topic>Analysis</topic><topic>Chlorophyll</topic><topic>Climate Change - 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subjects | Alzheimer's disease Alzheimers disease Analysis Chlorophyll Climate Change - statistics & numerical data Criteria Data processing Earth science Earth sciences Geovetenskap Gross Domestic Product - trends Hypotheses Hypothesis testing Mathematical analysis Mathematics Methods Models, Statistical NATURAL SCIENCES NATURVETENSKAP Nitrogen Phosphorus Probability Regression analysis Significance Software Spreadsheet software Statistical analysis Statistical significance Statistics Statistik Time series trend Trend analysis trendanalys Trends |
title | An operational definition of a statistically meaningful trend |
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