Page 7 - Math SL HB Sem 3

. Back-to-back stemplots

Srem and leaf diagrams can be used ao compare nvo samples by shorving the resulrs together
on a back-to-back stemplot-

Example 1.4

Use a stem and leaf diagram to compare the examinarion marks in French and English for a
class of 20 pupils,

Solution 1.4

The firsr iour enrries for French (7i,59, 58,5g) and tor English t.;2, i8, 5g,77) are enrercd
into a back-to-back sremplor as follows:
[:rcneh English
4"v.
3 s12
I
88 ) 2s
9 6 8
j 7
8
I he completed diagram, before rearranging, is
French English
72 3 8
74546 4 1.1 .1
731088 5 2S5
6119 6 8-ii39
85 7 791229
I 8 5l
-l-he
final diagram, arranged in order:
r Il ench E.rg Iish
27 3 8
7 65 44 4 311
8 8 73 30 5 268
)6 11 6 3jj 89
85 7 122 799
I 8 4i
From rhe diagram it is clear that rhe ciass had rrigher marks in Engli;ir than in French and it
appears rhat they performed bener in E.glish_ This.rould, ho,,*e.Ier, depeod on rhe standards
o[ marking r,scd in rhe ru.o examinarions-

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