[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-1-en-105":3,"doc-seo-564949-105":53,"doc-detail-564949-en":120},{"code":4,"msg":5,"data":6},0,"success",[7,14,19,24,29,34,39,44,49],{"id":8,"doc_module":9,"doc_module_name":10,"category_name":11,"show_sort_weight":12,"slug":13},11,1,"Template","Presentations",90,"presentations",{"id":15,"doc_module":9,"doc_module_name":10,"category_name":16,"show_sort_weight":17,"slug":18},12,"Resumes",80,"resumes",{"id":20,"doc_module":9,"doc_module_name":10,"category_name":21,"show_sort_weight":22,"slug":23},14,"Invoices",70,"invoices",{"id":25,"doc_module":9,"doc_module_name":10,"category_name":26,"show_sort_weight":27,"slug":28},15,"Posters",60,"posters",{"id":30,"doc_module":9,"doc_module_name":10,"category_name":31,"show_sort_weight":32,"slug":33},16,"Social Media",50,"social-media",{"id":35,"doc_module":9,"doc_module_name":10,"category_name":36,"show_sort_weight":37,"slug":38},17,"Forms",40,"forms",{"id":40,"doc_module":9,"doc_module_name":10,"category_name":41,"show_sort_weight":42,"slug":43},18,"Letters",30,"letters",{"id":45,"doc_module":9,"doc_module_name":10,"category_name":46,"show_sort_weight":47,"slug":48},21,"Paper Templates",5,"papers-templates",{"id":50,"doc_module":9,"doc_module_name":10,"category_name":51,"show_sort_weight":4,"slug":52},158,"General","general-158",{"code":4,"msg":54,"data":55},"ok",{"site_id":56,"language":57,"slug":58,"title":59,"keywords":60,"description":61,"schema_data":62,"social_meta":113,"head_meta":115,"extra_data":117,"updated_unix":119},105,"en","sop-20-standard-deviation-and-range-charts-standard-operating-procedure","SOP 20 - Standard Deviation and Range Charts - Standard Operating Procedure","","SOP 20 defines a standard operating procedure to monitor statistical control of measurement processes using standard deviation (sp) charts and optional range (R) charts. It applies to calibration methods where replicate measurements are performed but maintaining laboratory check standards is impractical. The procedure covers prerequisites, data collection with minimum replicate sets, calculation of pooled standard deviation, optional range evaluation, and chart construction using warning and action/control limits.",{"@graph":63,"@context":112},[64,80,95],{"@type":65,"itemListElement":66},"BreadcrumbList",[67,71,74,77],{"item":68,"name":69,"@type":70,"position":9},"https://docshare.wps.com","Home","ListItem",{"item":72,"name":10,"@type":70,"position":73},"https://docshare.wps.com/template/",2,{"item":75,"name":36,"@type":70,"position":76},"https://docshare.wps.com/template/forms/",3,{"item":78,"name":59,"@type":70,"position":79},"https://docshare.wps.com/template/sop-20-standard-deviation-and-range-charts-standard-operating-procedure/564949/",4,{"url":78,"name":59,"@type":81,"author":82,"headline":59,"publisher":85,"fileFormat":88,"inLanguage":57,"description":61,"dateModified":89,"datePublished":89,"encodingFormat":88,"isAccessibleForFree":90,"interactionStatistic":91},"DigitalDocument",{"name":83,"@type":84},"WPS_1786070896","Person",{"url":68,"name":86,"@type":87},"DocShare","Organization","application/pdf","2026-10-12",true,{"@type":92,"interactionType":93,"userInteractionCount":4},"InteractionCounter",{"@type":94},"ViewAction",{"@type":96,"mainEntity":97},"FAQPage",[98,104,108],{"name":99,"@type":100,"acceptedAnswer":101},"When should standard deviation charts be preferred over range charts?","Question",{"text":102,"@type":103},"Standard deviation charts are preferred for monitoring and evaluating process standard deviations when replicate measurements are made.","Answer",{"name":105,"@type":100,"acceptedAnswer":106},"How many replicate data sets are required before establishing an adequate database?",{"text":107,"@type":103},"A minimum of 12 sets of data must be available before a reasonably adequate data base is established.",{"name":109,"@type":100,"acceptedAnswer":110},"How is the range (R) calculated for replicate runs?",{"text":111,"@type":103},"When range is used, R represents the absolute difference of two (or more) replicate runs, using only absolute values to determine range and average range.","https://schema.org",{"og:url":78,"og:type":114,"og:title":59,"og:site_name":86,"og:description":61},"article",{"robots":116,"canonical":78},"index,follow",{"doc_id":118,"site_id":56},564949,1791845310,{"code":4,"msg":5,"data":121},{"doc_id":118,"user_id":122,"nickname":83,"user_avatar":123,"doc_module":9,"category_id":35,"category_name":36,"doc_title":59,"doc_description":61,"doc_content":124,"file_id":125,"file_url":126,"file_type":127,"file_size":128,"view_count":4,"is_deleted":4,"is_public":9,"is_downloadable":9,"audit_status":9,"page_count":129,"language":130,"language_code":57,"site_id":56,"html_lang":57,"table_of_contents":131,"faqs":132,"seo_title":133,"seo_description":61,"update_tm":119,"read_time":73},549768072016,"https://ap-avatar.wpscdn.com/davatar_155a257f0dc6eb9ab79c44ca47cae57d","This publication is available free of charge from: [https://doi.org/10.6028/NIST.IR.7383-2019](https://doi.org/10.6028/NIST.IR.7383-2019)  \nSOP 20  \nStandard Operating Procedure  \nfor  \nStandard Deviation and Range Charts  \n1 Introduction  \n Purpose  \nThis procedure describes a process to be followed to monitor the statistical control of a measurement process using standard deviation charts or range charts for any calibration method where replicate measurements are performed and where it is not practical or feasible to maintain laboratory check standards. Standard deviation charts are preferred to the use of range charts for monitoring and evaluating process standard deviations when replicate measurements are made.  \n Prerequisites  \nThe procedure must match the calibration procedure that is being monitored.  \n2 Summary  \nBecause of the size and cost of some laboratory standards, it is not always practical to have check standards remain in the laboratory for the purposes of measurement control. However, it is practical to maintain standard deviation (sp) charts or range (R) charts for each nominal size standard that is submitted to evaluate the standard deviation of replicate runs. Directions for preparing and using an R control chart that monitors the precision of the test procedure are given. It is assumed that standards of the same nominal capacity and design will have similar characteristics with respect to the repeatability of tests. Since it isnot practical to run a sufficient number of tests on each unknown standard to determine the repeatability, the absolute difference between replicate tests are graphed on the same sp or R chart to reflect the repeatability of measurement of the unknown standards tested in the laboratory. Note: Provers of similar readability may be grouped together on the same chart as long as results from different sized provers pass an F-test (e.g., provers greater than and equal to 500 gal generally have 20 in3 graduations and equivalent repeatability) .  \n3 Equipment  \nAll equipment is designated in the respective calibration SOP.  \n4 Procedure  \n Define: Determine appropriate measurement assurance  \nThe SOP used for calibration should contains instructions to define the type of measurement assurance and check standards to be measured and analyzed to ensure the process and standards are in control prior to reporting measurement values from calibrations.  \nThis publication is available free of charge from: [https://doi.org/10.6028/NIST.IR.7383-2019](https://doi.org/10.6028/NIST.IR.7383-2019)  \n Measure: Data Collection  \n Conduct the required number of replicates per test on the unknown test item per the designated SOP. A minimum of 12 sets of data must be available before a reasonably adequate data base is established. Note: 25 to 30 replicate sets of data are needed to determine valid uncertainties.  \n Tabulate the measured errors as determined by each of the two trials using a form such as the one contained in the Appendix. It is recommended that the data be maintained in a spreadsheet or other electronic program in lieu of a paper form. (If the unknown item is adjusted after the first run, the first trial reading after the adjustment is used in the evaluation) .  \n Analyze: Calculate the standard deviation (recommended)  \n A standard deviation of the replicate runs, sp, may be calculated for each set of runs according to the appropriate SOP. An accepted standard deviation over time is calculated as the pooled standard deviation to represent the accepted standard deviation of the measurement process. This pooled standard deviation may be used to perform F-tests as part of the SOP to immediately determine pass/fail status of the runs.  \n Analyze: Calculate the range (optional)  \n Where the range is used, it represents is the absolute difference of two (or more) replicate runs. Be sure that only absolute values are used in the determination of the range and average range!  \nR = x1 − x 2   Eqn. ( ","cbCaiiKJWXPatxsv","https://ap.wps.com/l/cbCaiiKJWXPatxsv","pdf",113636,6,"English","# 1 Introduction\n## Purpose\n## Prerequisites\n# 2 Summary\n# 3 Equipment\n# 4 Procedure\n## Define: Determine appropriate measurement assurance\n## Measure: Data Collection\n## Analyze: Calculate the standard deviation (recommended)\n## Analyze: Calculate the range (optional)\n## Construct Appropriate Charts","[{\"question\":\"When should standard deviation charts be preferred over range charts?\",\"answer\":\"Standard deviation charts are preferred for monitoring and evaluating process standard deviations when replicate measurements are made.\"},{\"question\":\"How many replicate data sets are required before establishing an adequate database?\",\"answer\":\"A minimum of 12 sets of data must be available before a reasonably adequate data base is established.\"},{\"question\":\"How is the range (R) calculated for replicate runs?\",\"answer\":\"When range is used, R represents the absolute difference of two (or more) replicate runs, using only absolute values to determine range and average range.\"}]","SOP 20 - Standard Deviation and Range Charts - Standard Operating Procedure | PDF"]