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Lady tasting tea

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20: 663:, revealed that in the actual experiment the lady succeeded in identifying all eight cups correctly. The chance of someone who just guesses of getting all correct, assuming she guesses that any four had the tea put in first and the other four the milk, would be only 1 in 70 (the combinations of 8 taken 4 at a time). 450:
indicating an incorrect cup which is chosen). Thus a selection of any one correct cup and any three incorrect cups can occur in any of 4×4 = 16 ways. The frequencies of the other possible numbers of successes are calculated correspondingly. Thus the number of successes is distributed according to the
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The critical region for rejection of the null of no ability to distinguish was the single case of 4 successes of 4 possible, based on the conventional probability criterion < 5%. This is the critical region because under the null of no ability to distinguish, 4 successes has 1 chance out of
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The frequencies of the possible numbers of successes, given in the final column of this table, are derived as follows. For 0 successes, there is clearly only one set of four choices (namely, choosing all four incorrect cups) giving this result. For one success and three failures, there are four
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The experiment provides a subject with eight randomly ordered cups of tea – four prepared by pouring milk and then tea, four by pouring tea and then milk. The subject attempts to select the four cups prepared by one method or the other, and may compare cups directly against each other as
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the lady properly categorized all 8 cups was Fisher willing to reject the null hypothesis – effectively acknowledging the lady's ability at a 1.4% significance level (but without quantifying her ability). Fisher later discussed the benefits of more trials and repeated tests.
79:. Her future husband, William Roach, suggested that Fisher give her eight cups, four of each variety, in random order. One could then ask what the probability was for her getting the specific number of cups she identified correct (in fact all eight), but just by chance. 541: 257: 113:
The test statistic is a simple count of the number of successful attempts to select the four cups prepared by a given method. The distribution of possible numbers of successes, assuming the
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Fisher's description is less than 10 pages in length and is notable for its simplicity and completeness regarding terminology, calculations and design of the experiment. The test used was
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ii. 19, "We may speak of this hypothesis as the 'null hypothesis' the null hypothesis is never proved or established, but is possibly disproved, in the course of experimentation."
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denoting a correct cup that is not chosen); and independently of that, there are four incorrect cups of which three are selected, which can occur in
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70 (≈ 1.4% < 5%) of occurring, whereas at least 3 of 4 successes has a probability of (16+1)/70 (≈ 24.3% > 5%).
838: 760:, Chapter II. The Principles of Experimentation, Illustrated by a Psycho-physical Experiment, Section 8. The Null Hypothesis. 23:
The experiment asked whether a taster could tell if the milk was added before the brewed tea, when preparing a cup of tea.
1012: 992: 912: 875: 76: 797: 1028: 979:. Institute of Mathematical Statistics Lecture Notes - Monograph Series. Hayward, CA.: IMS. pp. 13–31. 1038: 452: 65:, which is "never proved or established, but is possibly disproved, in the course of experimentation". 775: 57: 400: 347: 107: 699:" was "one of the two supporting pillars ... of the randomization analysis of experimental data." 1043: 103: 102:
is that the subject has no ability to distinguish the teas. In Fisher's approach, there was no
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Statistical Information and Likelihood : A Collection of Critical Essays by Dr. D. Basu
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th row of Pascal's triangle, such that each integer in the row is squared. In this case,
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correct cups of which one is selected, which by the combination formula can occur in
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The Lady Tasting Tea: How Statistics Revolutionized Science in the Twentieth Century
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is the number of success states in the population or four cups of either type, and
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The example is loosely based on an event in Fisher's life. The woman in question,
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is the number of draws, or four cups. The distribution of combinations for making
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desired. The method employed in the experiment is fully disclosed to the subject.
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is true, can be computed using the number of combinations. Using the
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Current Issues in Statistical Inference – Essays in Honor of D. Basu
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because 4 teacups are selected from the 8 available teacups.
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interpreted as an incorrect cup which is not chosen, and
252:{\displaystyle {\binom {8}{4}}={\frac {8!}{4!(8-4)!}}=70} 973:"Intervention experiments, randomization and inference" 563:
is the population size or total number of cups of tea,
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Tea-Tasting Distribution Assuming the Null Hypothesis
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wrote that "the famous case of the 'lady tasting tea
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ways (as shown in the second column, this time with
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whether the tea or the milk was added first to a cup
687:, which describes Fisher's experiment and ideas on 633: 595: 575: 555: 535: 467: 434: 381: 251: 165: 139: 196: 183: 1020: 927:Journal of the American Statistical Association 475:equal to the number of successes, we may write 975:. In Malay Ghosh and Pramod K. Pathak (ed.). 782: 420: 407: 367: 354: 666: 389:different ways (as shown in column 2, with 967: 393:denoting a correct cup that is chosen and 611:available selections corresponds to the 26: 18: 852: 850: 1021: 899: 821: 788: 757: 742: 455:. Specifically, for a random variable 921: 815: 333: 868:R.A. Fisher, The Life of a Scientist 847: 659:reports that a colleague of Fisher, 865: 827:"Mathematics of a Lady Tasting Tea" 13: 831:The World of Mathematics, volume 3 763: 411: 358: 304:ooxx, oxox, oxxo, xoxo, xxoo, xoox 187: 14: 1055: 89: 870:. New York: Wiley. p. 134. 1034:Statistical hypothesis testing 884: 859: 833:. Courier Dover Publications. 530: 494: 435:{\textstyle {\binom {4}{3}}=4} 382:{\textstyle {\binom {4}{1}}=4} 234: 222: 1: 829:. In James Roy Newman (ed.). 729: 75:, claimed to be able to tell 16:Famous randomized experiment 7: 1007:, W.H. Freeman / Owl Book. 907:(9th ed.). Macmillan. 890:Basu (1980a, p. 575; 1980b) 702: 453:hypergeometric distribution 10: 1060: 271:Combinations of selection 905:The Design of Experiments 866:Box, Joan Fisher (1978). 776:The Design of Experiments 273: 270: 267: 58:The Design of Experiments 55:and reported in his book 964:, editor. Springer 1988. 985:10.1214/lnms/1215458836 274:Number of Combinations 259:possible combinations. 173:cups chosen, there are 108:Neyman–Pearson approach 635: 607:selections out of the 597: 577: 557: 537: 469: 436: 383: 315:oxxx, xoxx, xxox, xxxo 293:ooox, ooxo, oxoo, xooo 253: 167: 141: 104:alternative hypothesis 32: 24: 1029:Design of experiments 823:Fisher, Sir Ronald A. 724:Binomial distribution 636: 598: 578: 558: 538: 470: 437: 384: 254: 168: 142: 49:randomized experiment 37:design of experiments 31:Ronald Fisher in 1913 30: 22: 1001:Salsburg, D. (2002) 684:The Lady Tasting Tea 668:The Lady Tasting Tea 619: 587: 567: 547: 479: 459: 401: 348: 177: 151: 125: 1039:Science experiments 634:{\displaystyle k=4} 264: 166:{\displaystyle k=4} 140:{\displaystyle n=8} 84:Fisher's exact test 791:"Lady Tasting Tea" 719:Randomization test 661:H. Fairfield Smith 631: 593: 573: 553: 533: 465: 432: 379: 262: 249: 163: 137: 33: 25: 969:Kempthorne, Oscar 901:Fisher, Ronald A. 840:978-0-486-41151-4 789:Sturdivant, Rod. 714:Random assignment 596:{\displaystyle n} 576:{\displaystyle K} 556:{\displaystyle N} 468:{\displaystyle X} 418: 365: 341: 340: 241: 194: 1051: 998: 950: 933:(371): 575–582. 918: 891: 888: 882: 881: 863: 857: 854: 845: 844: 819: 813: 812: 810: 808: 802: 796:. Archived from 795: 786: 780: 767: 761: 755: 746: 740: 709:Permutation test 698: 640: 638: 637: 632: 602: 600: 599: 594: 582: 580: 579: 574: 562: 560: 559: 554: 542: 540: 539: 534: 474: 472: 471: 466: 441: 439: 438: 433: 425: 424: 423: 410: 388: 386: 385: 380: 372: 371: 370: 357: 265: 261: 258: 256: 255: 250: 242: 240: 214: 206: 201: 200: 199: 186: 172: 170: 169: 164: 146: 144: 143: 138: 106:, unlike in the 45:lady tasting tea 1059: 1058: 1054: 1053: 1052: 1050: 1049: 1048: 1019: 1018: 1017: 995: 939:10.2307/2287648 915: 895: 894: 889: 885: 878: 864: 860: 856:Salsburg (2002) 855: 848: 841: 820: 816: 806: 804: 803:on 10 July 2004 800: 793: 787: 783: 768: 764: 756: 749: 741: 737: 732: 705: 696: 679:popular science 672: 620: 617: 616: 588: 585: 584: 568: 565: 564: 548: 545: 544: 480: 477: 476: 460: 457: 456: 419: 406: 405: 404: 402: 399: 398: 366: 353: 352: 351: 349: 346: 345: 215: 207: 205: 195: 182: 181: 180: 178: 175: 174: 152: 149: 148: 147:total cups and 126: 123: 122: 115:null hypothesis 100:null hypothesis 92: 63:null hypothesis 17: 12: 11: 5: 1057: 1047: 1046: 1041: 1036: 1031: 1016: 1015: 999: 993: 965: 951: 919: 913: 896: 893: 892: 883: 876: 858: 846: 839: 814: 781: 773:R. A. Fisher, 762: 747: 734: 733: 731: 728: 727: 726: 721: 716: 711: 704: 701: 681:book entitled 675:David Salsburg 671: 665: 657:David Salsburg 650:if and only if 630: 627: 624: 592: 572: 552: 532: 529: 526: 523: 520: 517: 514: 511: 508: 505: 502: 499: 496: 493: 490: 489:Hypergeometric 487: 484: 464: 431: 428: 422: 417: 414: 409: 378: 375: 369: 364: 361: 356: 339: 338: 335: 331: 330: 327: 324: 320: 319: 316: 313: 309: 308: 305: 302: 298: 297: 294: 291: 287: 286: 283: 280: 276: 275: 272: 269: 268:Success count 248: 245: 239: 236: 233: 230: 227: 224: 221: 218: 213: 210: 204: 198: 193: 190: 185: 162: 159: 156: 136: 133: 130: 121:formula, with 91: 90:The experiment 88: 73:Muriel Bristol 15: 9: 6: 4: 3: 2: 1056: 1045: 1044:Ronald Fisher 1042: 1040: 1037: 1035: 1032: 1030: 1027: 1026: 1024: 1014: 1013:0-8050-7134-2 1010: 1006: 1005: 1000: 996: 994:0-940600-24-2 990: 986: 982: 978: 974: 970: 966: 963: 959: 955: 952: 948: 944: 940: 936: 932: 928: 924: 920: 916: 914:0-02-844690-9 910: 906: 902: 898: 897: 887: 879: 877:0-471-09300-9 873: 869: 862: 853: 851: 842: 836: 832: 828: 824: 818: 799: 792: 785: 778: 777: 772: 766: 759: 754: 752: 744: 739: 735: 725: 722: 720: 717: 715: 712: 710: 707: 706: 700: 694: 690: 689:randomization 686: 685: 680: 676: 669: 664: 662: 658: 654: 651: 646: 642: 628: 625: 622: 614: 610: 606: 590: 570: 550: 527: 524: 521: 518: 515: 512: 509: 506: 503: 500: 497: 491: 488: 485: 482: 462: 454: 449: 445: 429: 426: 415: 412: 396: 392: 376: 373: 362: 359: 336: 332: 328: 325: 322: 321: 317: 314: 311: 310: 306: 303: 300: 299: 295: 292: 289: 288: 284: 281: 278: 277: 266: 260: 246: 243: 237: 231: 228: 225: 219: 216: 211: 208: 202: 191: 188: 160: 157: 154: 134: 131: 128: 120: 116: 111: 109: 105: 101: 96: 87: 85: 80: 78: 74: 71: 66: 64: 60: 59: 54: 53:Ronald Fisher 50: 46: 42: 38: 29: 21: 1002: 976: 957: 930: 926: 904: 886: 867: 861: 830: 817: 805:. Retrieved 798:the original 784: 774: 770: 765: 738: 682: 677:published a 673: 667: 655: 647: 643: 612: 608: 604: 447: 443: 394: 390: 342: 112: 97: 93: 81: 67: 56: 44: 34: 962:J. K. Ghosh 807:2 September 769:OED quote: 758:Fisher 1971 743:Fisher 1971 318:4 × 4 = 16 307:6 × 6 = 36 296:4 × 4 = 16 119:combination 70:phycologist 51:devised by 1023:Categories 730:References 329:1 × 1 = 1 285:1 × 1 = 1 41:statistics 903:(1971) . 825:(1956) . 492:⁡ 486:∼ 229:− 971:(1992). 954:Basu, D. 923:Basu, D. 703:See also 693:Deb Basu 543:, where 947:2287648 35:In the 1011:  991:  945:  911:  874:  837:  648:Thus, 334:Total 43:, the 943:JSTOR 801:(PDF) 794:(PDF) 47:is a 1009:ISBN 989:ISBN 909:ISBN 872:ISBN 835:ISBN 809:2018 771:1935 670:book 326:xxxx 282:oooo 98:The 981:doi 935:doi 337:70 39:in 1025:: 987:. 960:; 941:. 931:75 929:. 849:^ 750:^ 691:. 609:2k 247:70 110:. 86:. 997:. 983:: 949:. 937:: 917:. 880:. 843:. 811:. 697:' 629:4 626:= 623:k 613:k 605:k 591:n 571:K 551:N 531:) 528:4 525:= 522:n 519:, 516:4 513:= 510:K 507:, 504:8 501:= 498:N 495:( 483:X 463:X 448:o 444:x 430:4 427:= 421:) 416:3 413:4 408:( 395:o 391:x 377:4 374:= 368:) 363:1 360:4 355:( 323:4 312:3 301:2 290:1 279:0 244:= 238:! 235:) 232:4 226:8 223:( 220:! 217:4 212:! 209:8 203:= 197:) 192:4 189:8 184:( 161:4 158:= 155:k 135:8 132:= 129:n

Index



design of experiments
statistics
randomized experiment
Ronald Fisher
The Design of Experiments
null hypothesis
phycologist
Muriel Bristol
whether the tea or the milk was added first to a cup
Fisher's exact test
null hypothesis
alternative hypothesis
Neyman–Pearson approach
null hypothesis
combination
hypergeometric distribution
if and only if
David Salsburg
H. Fairfield Smith
David Salsburg
popular science
The Lady Tasting Tea
randomization
Deb Basu
Permutation test
Random assignment
Randomization test
Binomial distribution

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