In: Statistics and Probability
In a three-digit lottery, each of the three digits is supposed
to have the same probability of occurrence (counting initial blanks
as zeros, e.g., 32 is treated as 032). The table shows the
frequency of occurrence of each digit for 90 consecutive daily
three-digit drawings.
Digit | Frequency | ||
0 | 26 | ||
1 | 23 | ||
2 | 29 | ||
3 | 38 | ||
4 | 30 | ||
5 | 26 | ||
6 | 26 | ||
7 | 20 | ||
8 | 27 | ||
9 | 25 | ||
Total | 270 | ||
(a) Calculate the chi-square test statistic,
degrees of freedom, and the p-value. (Perform a
uniform goodness-of-fit test. Round your test statistic value to 2
decimal places and the p-value to 4 decimal
places.)
Test statistic | ||
d.f. | ||
p-value | ||
(b) Choose the correct answer by drawing a bar chart for
the above data.
The graph will reveal that 7 occurs least frequently.
The graph will reveal that 8 occurs least frequently.
The graph will reveal that 3 occurs least frequently.
The graph will reveal that 4 occurs least frequently.
(c) At α = .10, we cannot reject the hypothesis
that the digits are from a uniform population.
True
False
Chi square table | ||||
Digit | Frequency | E | O-E | (O-E)2/E |
0 | 26 | 27 | -1 | 0.037037 |
1 | 23 | 27 | -4 | 0.592593 |
2 | 29 | 27 | 2 | 0.148148 |
3 | 38 | 27 | 11 | 4.481481 |
4 | 30 | 27 | 3 | 0.333333 |
5 | 26 | 27 | -1 | 0.037037 |
6 | 26 | 27 | -1 | 0.037037 |
7 | 20 | 27 | -7 | 1.814815 |
8 | 27 | 27 | 0 | 0 |
9 | 25 | 27 | -2 | 0.148148 |
Total | 270 | 270 | 0 | 7.62963 |
expected count= | 270/10 =27 | |||
H0: | Digits are distributed uniformly | |||
H1: | Digits are not distributed uniformly | |||
(a)The chi-square test statistic = | 7.63 | |||
degrees of freedom = | 9 | |||
p-value = | 0 .5718 | |||
(b) The graph will reveal that 8 occurs least frequently.
(c) At α = .10, we cannot reject the hypothesis that the digits are from a uniform population.
True since p-value > 0.10