From: Ignacio Colonna <iacolonn_at_uiuc.edu>

Date: Tue 22 Mar 2005 - 03:41:45 EST

system i386, mingw32

status

major 2

minor 0.1

year 2004

month 11

day 15

language R

Date: Tue 22 Mar 2005 - 03:41:45 EST

José,

Notice that the values to the left of the | in your stem plot are all even. Odd numbers are included in the same line.

Try

> stem(time,scale=2)

The decimal point is 1 digit(s) to the right of the |

3 | 2 4 | 17 5 | 09 6 | 4667789 7 | 38 8 | 3 9 | 0335 10 | 00 11 | 0

ignacio

-----Original Message-----

From: r-help-bounces@stat.math.ethz.ch

[mailto:r-help-bounces@stat.math.ethz.ch] On Behalf Of Jose A. Hernandez
Sent: Monday, March 21, 2005 9:15 AM

To: r-help@stat.math.ethz.ch

Subject: [R] Bug on the stem function or in my brain ?

time, is time to complete the exam in minutes exam.1, is the grade for the exam

* > time
*

[1] 32 41 47 50 59 64 66 66 67 67 68 69 73 78 83 90
93 93 95

[20] 100 100 110

> stem(time)

The decimal point is 1 digit(s) to the right of the |

2 | 2 4 | 1709 6 | 466778938 8 | 30335 10 | 000

The stem and leaf plot does not reflect the actual data, the bottom line for instance says there were 3 people that spent 100 minutes working on the test. The next to bottom line says there were one 80, three 83s, one 85. And so forth.

> exam.1

[1] 82 100 86 81 88 78 92 23 91 49 97 9 89 78 93 60
80 80 83

[20] 94 51 100

The decimal point is 1 digit(s) to the right of the |

0 | 9 2 | 3 4 | 91 6 | 088 8 | 0012368912347 10 | 00

The Stem-and-Leaf plots DO NOT correspond to the data.

Any educational insights on this issue would be appreciated.

Regards,

Jose

> class(exam.1)

[1] "numeric"

> class(time)

[1] "numeric"

> version

_

platform i386-pc-mingw32

arch i386 os mingw32

system i386, mingw32

status

major 2

minor 0.1

year 2004

month 11

day 15

language R

-- Jose A. Hernandez Ph.D. Candidate Precision Agriculture Center Department of Soil, Water, and Climate University of Minnesota 1991 Upper Buford Circle St. Paul, MN 55108 Ph. (612) 625-0445, Fax. (612) 625-2208 ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.htmlReceived on Tue Mar 22 03:46:17 2005

*
This archive was generated by hypermail 2.1.8
: Fri 03 Mar 2006 - 03:30:52 EST
*