Your Practice Set – Applications and Interpretation for IBDP Mathematics
Exercise 69
1 . The number of products produced by a machine operator is studied . A sample of 30 observations is recorded on 30 different weeks . Let X be the number of products produced by the machine operator in a particular week . It is given that sn
� 5 .
( a ) Find sn � 1.
Let X be the mean of the sample . It is also given that there are 1770 products produced by the machine operator in these 30 weeks .
[ 2 ]
( b ) Find an unbiased estimate of the population mean . [ 2 ]
2 . The number of complaint calls in a customer service department is studied . A sample of
2
25 observations is recorded on 25 different working days . It is given that sn � 1
� 1.25 .
( a ) Find
2 s n
.
It is also given that an unbiased estimate of the population mean is 7.8 .
( b ) Find the total number of complaint calls in the department in these 25 working days .
[ 2 ]
[ 2 ]
3 . A random sample of size 60 is taken from a population . It is given that sn � 1
� 2.37 .
( a ) Find s n
.
It is also given that an unbiased estimate of the population mean is � 3.8 .
( b ) Find the total sum of numbers in the sample .
[ 2 ]
[ 2 ]
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