R help - Apr 2015 - Problem with predict.lm()

Dear Arnab,
?
Thank you very much for your reply. It does not give an error message.
The problem is that predict does "work and predict" on the old data
and does not make the predictions with the provided new data.
?
Best,
?
Martin
?
?

Gesendet:?Mittwoch, 29. April 2015 um 16:51 Uhr
Von:?"ARNAB KR MAITY" <arnab_stat at yahoo.com>
An:?"Martin Spindler" <Martin.Spindler at gmx.de>, "r-help
at r-project.org" <r-help at r-project.org>
Betreff:?Re: [R] Problem with predict.lm()

Hi,
?
It seems to be working in my R. Although it is throwing the warning message
?
Warning message:
?
'newdata' had 200 rows but variables found have 100 rows?
?
?y
? [1] -1.071307580 ?0.102414204 -0.965046207 ?1.386057875 ?0.726835339
? [6] -0.186549950 -0.777144258 ?1.137210314 -1.069446945 -0.696084338
?[11] -0.467686285 ?0.997316781 ?0.776265490 -1.385720997 -0.007438381
?[16] ?0.302821728 ?0.024075173 -0.590401970 ?0.877104292 ?0.652724314
?[21] ?2.142135078 ?2.023051454 -0.547221960 ?0.342600702 ?0.080848203
?[26] ?0.074609232 ?0.255946197 -0.191242759 ?1.036445108 ?0.895068954
?[31] ?0.589477883 ?0.123230750 ?1.467210735 -1.636657283 -0.131504288
?[36] -0.665000122 ?0.390977868 ?0.546802014 ?0.445498091 ?1.063872749
?[41] ?1.406788635 -0.037147550 -1.047190960 -0.189105987 ?0.069617165
?[46] -0.049760285 -1.454279226 ?0.358351554 ?0.246587937 -0.060735329
?[51] ?1.664530111 -0.475931484 ?0.405480604 ?1.560446941 -0.030537155
?[56] -1.060319583 -1.828624216 -0.429391165 ?0.301697744 -0.029593593
?[61] -1.696307754 ?0.342678986 -0.433965195 -0.947338037 ?0.318186677
?[66] ?0.539630789 -1.354555193 ?0.086168702 ?0.002950100 ?1.783486665
?[71] -1.182419158 -0.930524123 ?0.376579158 -1.085035387 ?1.186125702
?[76] ?0.719738391 -0.486692820 -2.105396602 ?0.531238276 ?1.302812739
?[81] ?0.347851244 ?0.016452693 ?0.417535566 ?0.277705766 ?2.286275977
?[86] ?1.610183518 ?2.032037030 ?1.319074179 ?1.129375593 ?0.176684807
?[91] -0.630517144 ?1.302785450 ?0.994275267 -0.060116993 -0.655966924
?[96] ?1.628197169 ?1.935532651 -1.635783346 -1.172511179
?1.238336597
> ynew
? ? ? ? ? ?1 ? ? ? ? ? ?2 ? ? ? ? ? ?3 ? ? ? ? ? ?4 ? ? ? ? ? ?5 ? ? ? ? ? ?6?
-0.270916637 ?0.169149841 ?0.191348061 -0.009541999 ?0.112027155 ?0.016242323?
? ? ? ? ? ?7 ? ? ? ? ? ?8 ? ? ? ? ? ?9 ? ? ? ? ? 10 ? ? ? ? ? 11 ? ? ? ? ? 12?
-0.062178365 ?0.275322344 ?0.397030485 ?0.565078468 ?0.301230303 ?0.305405674?
? ? ? ? ? 13 ? ? ? ? ? 14 ? ? ? ? ? 15 ? ? ? ? ? 16 ? ? ? ? ? 17 ? ? ? ? ? 18?
?0.552136794 -0.151275710 ?0.470280882 ?0.349631748 ?0.022005869 ?0.181384646?
? ? ? ? ? 19 ? ? ? ? ? 20 ? ? ? ? ? 21 ? ? ? ? ? 22 ? ? ? ? ? 23 ? ? ? ? ? 24?
?0.143719339 ?0.478791323 ?0.518731127 ?0.229860133 -0.199433324 ?0.310576455?
? ? ? ? ? 25 ? ? ? ? ? 26 ? ? ? ? ? 27 ? ? ? ? ? 28 ? ? ? ? ? 29 ? ? ? ? ? 30?
?0.127612633 -0.157347145 ?0.413807523 ?0.007961485 -0.288867750 ?0.208759771?
? ? ? ? ? 31 ? ? ? ? ? 32 ? ? ? ? ? 33 ? ? ? ? ? 34 ? ? ? ? ? 35 ? ? ? ? ? 36?
?0.286165027 ?0.299492579 ?0.197312294 ?0.135601904 ?0.452828662 ?0.187191405?
? ? ? ? ? 37 ? ? ? ? ? 38 ? ? ? ? ? 39 ? ? ? ? ? 40 ? ? ? ? ? 41 ? ? ? ? ? 42?
?0.335596502 -0.109960231 -0.303770506 -0.276385255 ?0.429700474 ?0.003930969?
? ? ? ? ? 43 ? ? ? ? ? 44 ? ? ? ? ? 45 ? ? ? ? ? 46 ? ? ? ? ? 47 ? ? ? ? ? 48?
?0.184186301 ?0.140858190 ?0.479882236 ?0.182523553 -0.133845870 ?0.443940376?
? ? ? ? ? 49 ? ? ? ? ? 50 ? ? ? ? ? 51 ? ? ? ? ? 52 ? ? ? ? ? 53 ? ? ? ? ? 54?
?0.070571673 -0.383780163 ?0.362153269 ?0.202527841 ?0.164299813 ?0.327998904?
? ? ? ? ? 55 ? ? ? ? ? 56 ? ? ? ? ? 57 ? ? ? ? ? 58 ? ? ? ? ? 59 ? ? ? ? ? 60?
?0.047612361 -0.032167295 ?0.060976285 ?0.231929803 -0.449532973 ?0.109925656?
? ? ? ? ? 61 ? ? ? ? ? 62 ? ? ? ? ? 63 ? ? ? ? ? 64 ? ? ? ? ? 65 ? ? ? ? ? 66?
?0.468842330 ?0.108507841 ?0.158697337 -0.125813680 ?0.501159861 ?0.101646132?
? ? ? ? ? 67 ? ? ? ? ? 68 ? ? ? ? ? 69 ? ? ? ? ? 70 ? ? ? ? ? 71 ? ? ? ? ? 72?
?0.194383106 -0.006185569 ?0.354467348 ?0.340013811 ?0.088757961 ?0.439984356?
? ? ? ? ? 73 ? ? ? ? ? 74 ? ? ? ? ? 75 ? ? ? ? ? 76 ? ? ? ? ? 77 ? ? ? ? ? 78?
?0.330976669 ?0.449337326 ?0.081841142 -0.190123754 ?0.337794560 -0.111895039?
? ? ? ? ? 79 ? ? ? ? ? 80 ? ? ? ? ? 81 ? ? ? ? ? 82 ? ? ? ? ? 83 ? ? ? ? ? 84?
?0.598231564 ?0.444399789 ?0.388313945 ?0.244270482 ?0.200026237 ?0.009025077?
? ? ? ? ? 85 ? ? ? ? ? 86 ? ? ? ? ? 87 ? ? ? ? ? 88 ? ? ? ? ? 89 ? ? ? ? ? 90?
?0.341093767 -0.164196034 ?0.825849472 ?0.325975911 ?0.494473323 ?0.270037159?
? ? ? ? ? 91 ? ? ? ? ? 92 ? ? ? ? ? 93 ? ? ? ? ? 94 ? ? ? ? ? 95 ? ? ? ? ? 96?
?0.369787280 ?0.247455471 ?0.282701738 -0.541688411 -0.145796547 ?0.073172268?
? ? ? ? ? 97 ? ? ? ? ? 98 ? ? ? ? ? 99 ? ? ? ? ?100?
?0.685833173 -0.079174316 -0.193161949 -0.137517175?
?
?
?

Arnab Kumar Maity
Graduate Teaching Assistant
Division of Statistics
Northern Illinois University
DeKalb,
Illinois 60115
U.S.A?

------------------------------------------------------------
From: Martin Spindler <Martin.Spindler at gmx.de>
To: r-help at r-project.org
Sent: Wednesday, April 29, 2015 9:21 AM
Subject: [R] Problem with predict.lm()
Dear all,
?
the following example somehow uses the "old data" (X) to make the
predictions, but not the new data Xnew as intended.
?
y <- rnorm(100)
X <- matrix(rnorm(100*10), ncol=10)
lm <- lm(y~X)
Xnew <- matrix(rnorm(100*20), ncol=10)
ynew <- predict(lm, newdata=as.data.frame(Xnew)) #prediction in not made for
Xnew
?
How can I foce predict.lm to use use the new data?
?
Thank you very much for your efforts in advance!
?
Best,
?
Martin

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?