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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 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 ? Good day R-ers! I was running the basic statistics for the exam that my students took last week and something does not make sense with the stem() fucntion. Here are two of my variables: time, is time to complete the exam in minutes exam.1, is the grade for the exam In stem(), to the left of the vertical bar are the leading digits of the grades. To the right of the vertical bar are the last digits of the grades. Each single digit on the right represents one grade. > 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 > stem(exam.1) 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.html