A student rolled a supposedly fair die 60 times, resulting in
the distribution of dots shown. Research question: At
α = .10, can you reject the hypothesis that the die is
fair?
Number of Dots | |||||||
1 | 2 | 3 | 4 | 5 | 6 | Total | |
Frequency | 9 | 16 | 11 | 12 | 6 | 6 | 60 |
Calculate the chi-square test statistic, degrees of freedom and the p-value. (Round your test statistic value to 2 decimal places and the p-value to 4 decimal places.)
Probability(Proportion) of getting any one of the 1 to 6 is 1/6
Ho: Die is fair i.e. p1=p2=p3=p4=p5=p6=1/6
So we have
Number of Dots | Observed Frequency | P | Expected Frequency(n*p) |
1 | 9 | 1/6 | 10 |
2 | 16 | 1/6 | 10 |
3 | 11 | 1/6 | 10 |
4 | 12 | 1/6 | 10 |
5 | 6 | 1/6 | 10 |
6 | 6 | 1/6 | 10 |
Total | n=60 | 1 | 60 |
Degrees of freedom = Number of category -1=6-1 = 5
We will use Ti84
Enter Observed Frequency in L1 And Expected frequency in L2
Then Press STAT...TESTS...X^2 GOF -Test...
Enter values as
Result is
Test Statistic = 7.40
P-Value = 0.1926
P-Value > α=0.10
So we fail to reject the hypothesis that die is fair.
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