Statistics: Spread, Ogives & Box Plots (Grade 11) — Worksheet & Memo

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Grade 11 · Statistics

Statistics: Spread, Ogives & Box Plots (Grade 11)

MEMORANDUM

Name:

Class:

Date:

Mark

/ 16

Answer all questions. Show all your working — marks are awarded for method as well as the final answer. Teacher copy: accept any correct equivalent method.

1
For the box-and-whisker diagram below, write down the five-number summary.
(2)
min = 12, Q₁ = 24, median = 33, Q₃ = 42, max = 55✓✓ (2)
2
Calculate the interquartile range from the diagram below.
(2)
42 − 24 = 18✓✓ (2)
3
Calculate the mean of 12 ; 15 ; 18 ; 18 ; 21 ; 24 ; 27 ; 30 ; 33.
(2)
1989 = 22,00✓✓ (2)
4
Calculate the standard deviation of 12 ; 15 ; 18 ; 18 ; 21 ; 24 ; 27 ; 30 ; 33.
(2)
variance = 44,00 → σ = 6,63✓✓ (2)
5
How many data values lie within one standard deviation of the mean for the data above?
(2)
Interval [15,37 ; 28,63] contains 5 values✓✓ (2)
6
Use the ogive below to estimate the median mark.
(2)
The 20th of 40 values → ≈ 25 marks✓✓ (2)
7
Use the ogive below to write down the total number of learners.
(2)
40✓✓ (2)
8
Determine the outlier boundaries for the box plot below.
(2)
IQR = 18, 1,5×18 = 27 → below −3 or above 69; there are no outliers✓✓ (2)

TOTAL: 16 marks