Page 6 - Math SL HB Sem 3

STEM AND LEAF DIAGRAMS (STEMPLOTS)

1_]:1 ::.fu, way of gr,-ouprng data into classes while still reraining the original data is ro
draw a stem and leal diagram, also known as a stemplot.
These are rhe marks of 20 studenrs in an assignmenr:

g4..,
Norice rhat the lorvesr mark is/I7,and the highesr mark is
ln stem and leaf diagrams, all thi inrervals must be of equaY*idrh, so rr seems sensible ro
choose intervals t}-t9,20-29,30-39, g0_g9 fo. thi, d"r". '
...,
I Take the srem to represenr rhe rens and the leaf to represent rhe units.
The first five enrries '!(hen
all rlre numbers
84, 17, 38, 45 and 47
have been enrered the
are represented like this:
diagram looks like rhis:
Stem Leal
(tens) (units)
sler)r Lcaf
1 7 I 79
2
2 2
3 8 l 839
4 57 57
4
5 3.1 iJ l4
5
5 65
6
7 7 6s2
8 l
8 4
The enrries i, each leaf are norv arrangcd in numerical ordcr and a key is given ro exprain the
stem and leaf- The final diagram looks like rhis:
Stem and leaf diagram to show assignment marks
Stem LeaI
79
1,
z 2
3 389
4 57
5 134445
5
7 256
8 4

NOTE: The kev is essenrial in explaining how rhe sremplor has been formed-
In a stem and leaf diagrim, or stemplot

(a) equal intervals must be chosen,
(b) a key is esseorial.

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