Jellybeans

Jellybeans

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about reading information from a graph.

jelly beans

Jane's maths class estimated the number of jellybeans in a jar.

The students' estimates are shown on the graph below:

 

illustration: jellybeans

a)
What type of graph is this?
 
  (A)
(B)
(C)
(D)
(E)		 Dot plot
Histogram
Pictograph
Stem-and-leaf graph
Strip graph
 
b)
Altogether, how many students are in Jane's class? _____________
 
c) What is the:
 
 
i)
 
ii)
lowest estimate?       ____________
 
highest estimate?      ____________
 
d) What is the:
 
 
i)
 
ii)
median?   ____________
 
mode?      ____________
Task administration: 
This task is completed with pencil and paper only.
Level:
4
Curriculum info: 
Maths, Statistics, Statistical investigations
Keywords: 
stem-and-leaf graphs, graph interpretation, range, median, mode
Description of task: 
This task requires students to interpret a stem-and-leaf graph made by a class showing estimates of jelly beans in a jar.
Curriculum Links: 
This resource can be used to help to identify students' ability to identify information on a stem-and-leaf graph.
Learning Progression Frameworks
This resource can provide evidence of learning associated with
Statistical investigations, set 5
within the Mathematics Learning Progressions Frameworks.
Read more about the Learning Progressions Frameworks.
Answers/responses: 
  Y9 (04/1999)
a)   D [Stem-and-leaf graph] easy
b)   21 moderate
c) i)
ii)		 40
95		 difficult
difficult
d) i)
ii)		 75
88		 very difficult
very difficult
Diagnostic and formative information: 
  Common error Likely calculation Likely reason
a) Strip Graph (29%)    
b) 39
27		 4 + 5 + 6 + 7 + 8 + 9
21 + 6		 Adds the numbers on the stem.
Number of data points (leaves) plus number of categories (stems).
c)i)
   ii)
d)i)
   ii)		 0
9
5
8		   Reads the leaves as if they are the data (e.g., 0 instead of 40).
c)i)
   ii)		 15
68889		   Reads the leaves as a compact numeral.