In: Statistics and Probability
In a four-digit lottery, each of the four digits is supposed to
have the same probability of occurrence. The table shows the
frequency of occurrence of each digit for 87 consecutive daily
four-digit drawings.
Digit | Frequency | ||
0 | 37 | ||
1 | 40 | ||
2 | 31 | ||
3 | 43 | ||
4 | 34 | ||
5 | 31 | ||
6 | 37 | ||
7 | 29 | ||
8 | 30 | ||
9 | 36 | ||
Total | 348 | ||
(b) 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.)
Test statistic | |
d.f. | |
p-value | |
(c) Find the critical value of the chi-square for
α = .01. (Round your answer to 2 decimal
places.)
Critical value:
observed frequencey, O | expected proportion | expected frequency,E | (O-E) | (O-E)²/E | |
37 | 0.100 | 34.80 | 2.20 | 0.139 | |
40 | 0.100 | 34.80 | 5.20 | 0.777 | |
31 | 0.100 | 34.80 | -3.80 | 0.415 | |
43 | 0.100 | 34.80 | 8.20 | 1.932 | |
34 | 0.100 | 34.80 | -0.80 | 0.018 | |
31 | 0.100 | 34.800 | -3.80 | 0.415 | |
37 | 0.100 | 34.800 | 2.20 | 0.139 | |
29 | 0.100 | 34.800 | -5.80 | 0.967 | |
30 | 0.100 | 34.800 | -4.80 | 0.662 | |
36 | 0.100 | 34.800 | 1.20 | 0.041 |
b)
chi square test statistic,X² = Σ(O-E)²/E =
5.51
Degree of freedom=k-1= 10
- 1 = 9
P value = 0.7882 [ excel function:
=chisq.dist.rt(test-stat,df) ]
c)
Critical value = 21.67
Decision: P value >α , Do not reject Ho |