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Continuous or discrete variable

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582: 57: 413: 624:. In other words, a discrete variable over a particular interval of real values is one for which, for any value in the range that the variable is permitted to take on, there is a positive minimum distance to the nearest other permissible value. The value of a discrete variable can be obtained by counting, and the number of permitted values is either finite or 743:. An example of a mixed model could be a research study on the risk of psychological disorders based on one binary measure of psychiatric symptoms and one continuous measure of cognitive performance. Mixed models may also involve a single variable that is discrete over some range of the number line and continuous at another range. 677:
related to each other are 0-1 variables, being permitted to take on only those two values. The purpose of the discrete values of 0 and 1 is to use the dummy variable as a ‘switch’ that can ‘turn on’ and ‘turn off’ by assigning the two values to different parameters in an equation. A variable of this
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that is discrete or everywhere-continuous. An example of a mixed type random variable is the probability of wait time in a queue. The likelihood of a customer experiencing a zero wait time is discrete, while non-zero wait times are evaluated on a continuous time scale. In physics (particularly
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Methods of calculus do not readily lend themselves to problems involving discrete variables. Especially in multivariable calculus, many models rely on the assumption of continuity. Examples of problems involving discrete variables include
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Poyton, A. A.; Varziri, Mohammad Saeed; McAuley, Kimberley B.; MclellanPat James, Pat James; Ramsay, James O. (February 15, 2006). "Parameter estimation in continuous-time dynamic models using principal differential analysis".
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is commonly employed. In the case of regression analysis, a dummy variable can be used to represent subgroups of the sample in a study (e.g. the value 0 corresponding to a constituent of the control group).
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In probability theory and statistics, the probability distribution of a mixed random variable consists of both discrete and continuous components. A mixed random variable does not have a
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and quantitative (numerical). Continuous and discrete variables are subcategories of quantitative variables. Note that this schematic is not exhaustive in terms of the types of variables.
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gap on each side of it containing no values that the variable can take on, then it is discrete around that value. In some contexts, a variable can be discrete in some ranges of the
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values such that it can also take on all real values between them (including values that are arbitrarily or infinitesimally close together), the variable is continuous in that
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This is an image of vials with different amounts of liquid. A continuous variable could be the volume of liquid in the vials. A discrete variable could be the number of vials.
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are often used to treat continuous and discrete components in a unified manner. For example, the previous example might be described by a probability density
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A mixed multivariate model can contain both discrete and continuous variables. For instance, a simple mixed multivariate model could have a discrete variable
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Sharma, Shalendra D. (March 1975). "On a Continuous/Discrete Time Queueing System with Arrivals in Batches of Variable Size and Correlated Departures".
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Fitzmaurice, Garrett M.; Laird, Nan M. (March 1997). "Regression Models for Mixed Discrete and Continuous Responses with Potentially Missing Values".
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Brzychczy, Stanisaw; Gorniewicz, Lech (2011). "Continuous and discrete models of neural systems in infinite-dimensional abstract spaces".
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is a well-defined concept that takes the ratio of the change in the dependent variable to the independent variable at a specific instant.
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is continuous, if it can take on any value in that range. The reason is that any range of real numbers between
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Dekking, Frederik Michel; Kraaikamp, Cornelis; Lopuhaä, Hendrik Paul; Meester, Ludolf Erwin (2005).
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is treated as continuous, and the equation describing the evolution of some variable over time is a
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Introduction to Digital Signal Processing Using MATLAB with Application to Digital Communications
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In statistics, the probability distributions of discrete variables can be expressed in terms of
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Miller, Jerry L.L.; Erickson, Maynard L. (May 1974). "On Dummy Variable Regression Analysis".
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if and only if there exists a one-to-one correspondence between this variable and a subset of
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is treated as discrete, and the equation of evolution of some variable over time is called a
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are often used in problems in which the variables are continuous, for example in continuous
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is a variable whose value is obtained by measuring, i.e., one which can take on an
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Regression with Dummy Variables (Quantitative Applications in the Social Sciences)
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Classical Recursion Theory: The Theory of Functions and Sets of Natural Numbers
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quantum mechanics, where this sort of distribution often arises),
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is uncountable, with infinitely many values within the range.
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For example, a variable over a non-empty range of the
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of continuous variables can be expressed in terms of
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Common examples are variables that must be 342: 1357: 1308:Odifreddi, Piergiorgio (February 18, 1992). 699:Mixture of continuous and discrete variables 1382: 810:{\displaystyle p(t)=\alpha \delta (t)+g(t)} 523:{\displaystyle a,b\in \mathbb {R} ;a\neq b} 32:Discrete-time and continuous-time variables 1332: 1055: 349: 335: 1477: 1460:Olkin, Ingram; Tate, Robert (June 1961). 1459: 1307: 1126: 1116: 1083: 1073: 606: 504: 673:, sometimes some of the variables being 580: 411: 1435:Hardy, Melissa A. (February 25, 1993). 1153:, 1989, New Age International Limited, 14: 1546: 1519: 424: 1466:The Annals of Mathematical Statistics 1434: 1283:Computers & Chemical Engineering 589: 1410:Sociological Methods & Research 1151:Foundations of Discrete Mathematics 24: 1335:Handbook of Set-Theoretic Topology 981:Continuous-time stochastic process 855: 381:if they are typically obtained by 25: 1565: 1295:10.1016/j.compchemeng.2005.11.008 1200:Linear and nonlinear optimization 1105:Indian Dermatology Online Journal 976:Discrete time and continuous time 1011:Continuous series representation 986:Discrete-time stochastic process 748:cumulative distribution function 55: 1513: 1486: 1453: 1428: 1401: 1376: 1351: 946:Continuous or discrete spectrum 1522:Journal of Applied Probability 1326: 1301: 1273: 1186: 1159: 1143: 1092: 1049: 1016:Discrete series representation 928:{\displaystyle P(t=0)=\alpha } 916: 904: 869: 863: 839: 827: 804: 798: 789: 783: 771: 765: 122:Collectively exhaustive events 13: 1: 1062:Indian Journal of Anaesthesia 1042: 594:In contrast, a variable is a 554:probability density functions 1241:Springer Texts in Statistics 1193:Griva, Igor; Nash, Stephen; 1180:10.1016/j.neucom.2010.11.005 613:{\displaystyle \mathbb {N} } 576:instantaneous rate of change 7: 938: 10: 1570: 1422:10.1177/004912417400200402 1383:Thyagarajan, K.S. (2019). 686:is a dummy variable, then 645:probability mass functions 409:and continuous in others. 29: 1333:van Douwen, Eric (1984). 550:probability distributions 418:qualitative (categorical) 1554:Mathematical terminology 1118:10.4103/idoj.IDOJ_468_18 1075:10.4103/0019-5049.190623 292:Law of total probability 287:Conditional independence 176:Exponential distribution 161:Probability distribution 30:Not to be confused with 1479:10.1214/aoms/1177705052 654:dynamics, the variable 271:Conditional probability 929: 888: 811: 737: 717: 669:and more generally in 614: 586: 524: 478: 458: 421: 213:Continuous or discrete 166:Bernoulli distribution 1249:10.1007/1-84628-168-7 930: 889: 812: 753:dirac delta functions 738: 718: 615: 584: 572:differential equation 525: 479: 459: 415: 171:Binomial distribution 18:Quantitative variable 991:Continuous modelling 961:Discrete mathematics 898: 821: 759: 727: 707: 602: 488: 468: 448: 297:Law of large numbers 266:Marginal probability 191:Poisson distribution 40:Part of a series on 1001:Continuous geometry 966:Continuous spectrum 951:Continuous function 859: 688:logistic regression 671:regression analysis 660:difference equation 638:integer programming 431:continuous variable 425:Continuous variable 256:Complementary event 198:Probability measure 186:Pareto distribution 181:Normal distribution 996:Discrete modelling 925: 884: 845: 807: 733: 713: 684:dependent variable 626:countably infinite 610: 587: 546:statistical theory 520: 474: 454: 422: 307:Boole's inequality 243:Stochastic process 132:Mutual exclusivity 49:Probability theory 1369:978-1-4613-0893-5 1344:978-0-444-86580-9 1258:978-1-85233-896-1 1210:978-0-89871-661-0 1174:(17): 2711–2715. 1006:Discrete geometry 971:Discrete spectrum 736:{\displaystyle y} 716:{\displaystyle x} 692:probit regression 678:type is called a 596:discrete variable 590:Discrete variable 477:{\displaystyle b} 457:{\displaystyle a} 369:, a quantitative 359: 358: 261:Joint probability 208:Bernoulli process 107:Probability space 16:(Redirected from 1561: 1538: 1537: 1517: 1511: 1510: 1490: 1484: 1483: 1481: 1457: 1451: 1450: 1432: 1426: 1425: 1405: 1399: 1398: 1380: 1374: 1373: 1355: 1349: 1348: 1330: 1324: 1323: 1305: 1299: 1298: 1277: 1271: 1270: 1232: 1223: 1222: 1190: 1184: 1183: 1163: 1157: 1147: 1141: 1140: 1130: 1120: 1096: 1090: 1089: 1087: 1077: 1053: 1031:Discrete measure 934: 932: 931: 926: 893: 891: 890: 885: 858: 853: 816: 814: 813: 808: 742: 740: 739: 734: 722: 720: 719: 714: 619: 617: 616: 611: 609: 529: 527: 526: 521: 507: 483: 481: 480: 475: 463: 461: 460: 455: 351: 344: 337: 127:Elementary event 59: 37: 36: 21: 1569: 1568: 1564: 1563: 1562: 1560: 1559: 1558: 1544: 1543: 1542: 1541: 1534:10.2307/3212413 1518: 1514: 1507:10.2307/2533101 1491: 1487: 1458: 1454: 1447: 1433: 1429: 1406: 1402: 1395: 1381: 1377: 1370: 1356: 1352: 1345: 1331: 1327: 1320: 1306: 1302: 1278: 1274: 1259: 1233: 1226: 1211: 1191: 1187: 1164: 1160: 1148: 1144: 1097: 1093: 1054: 1050: 1045: 1040: 941: 899: 896: 895: 854: 849: 822: 819: 818: 760: 757: 756: 728: 725: 724: 708: 705: 704: 701: 622:natural numbers 605: 603: 600: 599: 592: 566:, the variable 561:continuous-time 503: 489: 486: 485: 469: 466: 465: 449: 446: 445: 435:uncountable set 427: 355: 203:Random variable 154:Bernoulli trial 35: 28: 23: 22: 15: 12: 11: 5: 1567: 1557: 1556: 1540: 1539: 1528:(1): 115–129. 1512: 1501:(1): 110–122. 1485: 1472:(2): 448–465. 1452: 1445: 1427: 1416:(4): 395–519. 1400: 1394:978-3319760285 1393: 1375: 1368: 1350: 1343: 1325: 1319:978-0444894830 1318: 1300: 1289:(4): 698–708. 1272: 1257: 1224: 1209: 1185: 1168:Neurocomputing 1158: 1142: 1091: 1068:(9): 662–669. 1047: 1046: 1044: 1041: 1039: 1038: 1036:Discrete space 1033: 1028: 1023: 1021:Discretization 1018: 1013: 1008: 1003: 998: 993: 988: 983: 978: 973: 968: 963: 958: 953: 948: 942: 940: 937: 924: 921: 918: 915: 912: 909: 906: 903: 883: 880: 877: 874: 871: 868: 865: 862: 857: 852: 848: 844: 841: 838: 835: 832: 829: 826: 806: 803: 800: 797: 794: 791: 788: 785: 782: 779: 776: 773: 770: 767: 764: 732: 712: 700: 697: 680:dummy variable 608: 591: 588: 519: 516: 513: 510: 506: 502: 499: 496: 493: 473: 453: 426: 423: 357: 356: 354: 353: 346: 339: 331: 328: 327: 326: 325: 320: 312: 311: 310: 309: 304: 302:Bayes' theorem 299: 294: 289: 284: 276: 275: 274: 273: 268: 263: 258: 250: 249: 248: 247: 246: 245: 240: 235: 233:Observed value 230: 225: 220: 218:Expected value 215: 210: 200: 195: 194: 193: 188: 183: 178: 173: 168: 158: 157: 156: 146: 145: 144: 139: 134: 129: 124: 114: 109: 101: 100: 99: 98: 93: 88: 87: 86: 76: 75: 74: 61: 60: 52: 51: 45: 44: 26: 9: 6: 4: 3: 2: 1566: 1555: 1552: 1551: 1549: 1535: 1531: 1527: 1523: 1516: 1508: 1504: 1500: 1496: 1489: 1480: 1475: 1471: 1467: 1463: 1456: 1448: 1442: 1438: 1431: 1423: 1419: 1415: 1411: 1404: 1396: 1390: 1386: 1379: 1371: 1365: 1361: 1354: 1346: 1340: 1336: 1329: 1321: 1315: 1311: 1304: 1296: 1292: 1288: 1284: 1276: 1268: 1264: 1260: 1254: 1250: 1246: 1242: 1238: 1231: 1229: 1220: 1216: 1212: 1206: 1202: 1201: 1196: 1195:Sofer, Ariela 1189: 1181: 1177: 1173: 1169: 1162: 1155: 1152: 1146: 1138: 1134: 1129: 1124: 1119: 1114: 1110: 1106: 1102: 1095: 1086: 1081: 1076: 1071: 1067: 1063: 1059: 1052: 1048: 1037: 1034: 1032: 1029: 1027: 1026:Interpolation 1024: 1022: 1019: 1017: 1014: 1012: 1009: 1007: 1004: 1002: 999: 997: 994: 992: 989: 987: 984: 982: 979: 977: 974: 972: 969: 967: 964: 962: 959: 957: 954: 952: 949: 947: 944: 943: 936: 922: 919: 913: 910: 907: 901: 881: 878: 875: 872: 866: 860: 850: 846: 842: 836: 833: 830: 824: 801: 795: 792: 786: 780: 777: 774: 768: 762: 754: 749: 744: 730: 710: 696: 693: 689: 685: 681: 676: 672: 668: 663: 661: 657: 653: 652:discrete time 648: 646: 641: 639: 633: 631: 627: 623: 620:, the set of 597: 583: 579: 577: 573: 569: 565: 562: 557: 555: 551: 547: 542: 540: 536: 531: 517: 514: 511: 508: 500: 497: 494: 491: 471: 451: 443: 438: 436: 432: 419: 414: 410: 408: 404: 403:infinitesimal 400: 396: 392: 391: 386: 385: 380: 376: 372: 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Joshi, 1145: 1111:(1): 82–86. 1108: 1104: 1094: 1065: 1061: 1051: 817:, such that 745: 702: 667:econometrics 664: 655: 649: 642: 634: 595: 593: 567: 558: 543: 539:optimization 532: 442:real numbers 439: 430: 428: 388: 382: 378: 374: 360: 323:Tree diagram 318:Venn diagram 282:Independence 228:Markov chain 212: 112:Sample space 675:empirically 533:Methods of 437:of values. 407:number line 363:mathematics 238:Random walk 79:Determinism 67:Probability 1495:Biometrics 1446:0803951280 1043:References 956:Count data 541:problems. 375:continuous 367:statistics 149:Experiment 96:Randomness 42:statistics 1267:1431-875X 1219:236082842 1156:, page 7. 923:α 882:α 879:− 856:∞ 847:∫ 781:δ 778:α 682:. If the 515:≠ 501:∈ 384:measuring 142:Singleton 1548:Category 1197:(2009). 1137:30775310 939:See also 630:integers 564:dynamics 535:calculus 399:interval 390:counting 379:discrete 371:variable 223:Variance 1128:6362742 1085:5037948 373:may be 137:Outcome 1443:  1391:  1366:  1341:  1316:  1265:  1255:  1217:  1207:  1135:  1125:  1082:  894:, and 574:. The 548:, the 84:System 72:Axioms 484:with 117:Event 1441:ISBN 1389:ISBN 1364:ISBN 1339:ISBN 1314:ISBN 1263:ISSN 1253:ISBN 1215:OCLC 1205:ISBN 1133:PMID 834:> 656:time 568:time 464:and 395:real 365:and 1530:doi 1503:doi 1474:doi 1418:doi 1291:doi 1245:doi 1176:doi 1123:PMC 1113:doi 1080:PMC 1070:doi 690:or 665:In 650:In 559:In 544:In 387:or 377:or 361:In 1550:: 1526:12 1524:. 1499:53 1497:. 1470:32 1468:. 1464:. 1412:. 1287:30 1285:. 1261:. 1251:. 1243:. 1239:. 1227:^ 1213:. 1172:74 1170:. 1131:. 1121:. 1109:10 1107:. 1103:. 1078:. 1066:60 1064:. 1060:. 935:. 647:. 640:. 556:. 429:A 1536:. 1532:: 1509:. 1505:: 1482:. 1476:: 1449:. 1424:. 1420:: 1414:2 1397:. 1372:. 1347:. 1322:. 1297:. 1293:: 1269:. 1247:: 1221:. 1182:. 1178:: 1139:. 1115:: 1088:. 1072:: 920:= 917:) 914:0 911:= 908:t 905:( 902:P 876:1 873:= 870:) 867:t 864:( 861:g 851:0 843:= 840:) 837:0 831:t 828:( 825:P 805:) 802:t 799:( 796:g 793:+ 790:) 787:t 784:( 775:= 772:) 769:t 766:( 763:p 731:y 711:x 607:N 518:b 512:a 509:; 505:R 498:b 495:, 492:a 472:b 452:a 350:e 343:t 336:v 34:. 20:)

Index

Quantitative variable
Discrete-time and continuous-time variables
statistics
Probability theory

Probability
Axioms
Determinism
System
Indeterminism
Randomness
Probability space
Sample space
Event
Collectively exhaustive events
Elementary event
Mutual exclusivity
Outcome
Singleton
Experiment
Bernoulli trial
Probability distribution
Bernoulli distribution
Binomial distribution
Exponential distribution
Normal distribution
Pareto distribution
Poisson distribution
Probability measure
Random variable

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