Apps. and Interpretation for IBDP Maths Ebook 1 | Page 345

The critical value is given by 16.919.
(e)
State the conclusion of the test with a reason.
[2]
3. In January 2020, the number of emails received on each day is recorded. The following
table shows the expected frequencies and the observed frequencies of the outcomes:
Number of emails 0 1 2 3 4 5
Expected frequency a 8 8 6 3 2
Observed frequency 2 6 6 6 6 b
A
2
� goodness of fit test is conducted at a 5% significance level.
(a)
Write down the null hypothesis of the test.
(b) Write down the values of a and b .
(c)
(d)
(e)
Write down the degree of freedom of the test.
Find the p -value.
State the conclusion of the test with a reason.
4. In an experiment, a biased seven-sided die is tossed for 120 times. The following table
shows the expected frequencies and the observed frequencies of the outcomes:
[1]
[2]
[1]
[2]
[2]
Outcome 1 2 3 4 5 6 7
Expected frequency 15 15 15 e 15 15 15
Observed frequency 16 19 8 28 9 32 8
23
A
2
� goodness of fit test is conducted at a 1% significance level.
(a) Write down the null hypothesis of the test.
(b) Write down the value of e .
(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.
[1]
[1]
[1]
[2]
[2]
335
www.seprodstore.com