Apps. and Interpretation for IBDP Maths Ebook 1 | Page 349

(d)
(e)
Find the p -value.
State the conclusion of the test with a reason.
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4. The following table shows the distribution of the ages of staffs in an office and their
number of investment bank accounts:
Age
Number of investment bank accounts
Zero One Two Three Four Total
18 to 37 x 4 5 3 1 18
38 to 57 y 5 4 2 1 16
58 to 77 11 2 1 1 1 16
Total 20 11 10 6 3 50
A
2
� test for independence is conducted at a 5% significance level.
(a) Write down the null hypothesis of the test.
(b) Write down the values of x and y .
(c) Write down the degree of freedom of the test.
(d) Find the p -value.
(e) State the conclusion of the test with a reason.
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[2]
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