296 Analysis of discrete data (Chapter 13)4 A sample of 15 measurements has a mean of 14 : 2 and a sample of 10 measurements has a mean
of 12 : 6. Find the mean of the total sample of 25 measurements.
5 Determine the mean of the numbers 7 , 5 , 7 , 2 , 8 and 7. If two additional numbers, 2 andx, reduce
the mean by 1 , findx.6 Jenny’s golf scores for her
last 20 rounds were:90 106 84 103 112 100 105 81 104 98
107 95 104 108 99 101 106 102 98 101
a Find the median, lower quartile and upper quartile of the data set.
b Find the interquartile range of the data set and explain what it represents.Stem Leaf
3 89
4 225
5 01179
6 134
7 07 j 0 represents 707 For the data displayed in the stem-and-leaf plot find the:
a mean b median
c lower quartile d upper quartile
e range f interquartile rangeScore Frequency
6 2
7 4
8 7
9 12
10 5
Total 308 The given table shows the distribution of scores for a Year 10 spelling test
in Austria.
a Calculate the: i mean ii mode
iii median iv range of the scores
b The average score for all Year 10 students across Austria in this
spelling test was 6 : 2. How does this class compare to the national
average?
c The data set is skewed. Is the skewness positive or negative?No. of times Frequency
0 - 4 19
5 - 9 24
10 - 14 10
15 - 19 5
20 - 24 29 Sixty people were asked: “How many times have you been to the
cinema in the last twelve months?”. The results are given in the
table alongside.
Estimate the mean and median of the data.10 The data below shows the number of pages contained
in a random selection of books from a library:
295 612 452 182 335 410 256 715 221 375
508 310 197 245 411 162 95 416 372 777
411 236 606 192 487
a Use technology to find the:
i mean ii median
iii lower quartile iv upper quartile
b Find the range and interquartile range for the data.IGCSE01
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Y:\HAESE\IGCSE01\IG01_13\296IGCSE01_13.CDR Thursday, 23 October 2008 3:59:03 PM PETER