1.Before the presidential debates, it was expected that the percentages of registered voters in favor of various candidates to be as follows.
After the presidential debates, a random sample of 1200 voters showed that 540 favored the Democratic candidate; 480 were in favor of the Republican candidate; 40 were in favor of the Independent candidate, and 140 were undecided. At 95% confidence, test to see if the proportion of voters has changed.
2.The number of emergency calls per day at a hospital over a period of 120 days is shown below:
Emergency Calls (x)Frequency (f)
Use a = 0.05 and test to see if the above data have a Poisson distribution.
- 4 年前最佳解答
p-value is between .025 and .05; reject H0; there has been a change
critical value is 7.815; reject H0; there has been a change.
X^= 4.72; p-value is greater than 0.1, do not reject H0; distribution is Poisson (critical X^= 11.070)參考資料： 統計大刀題庫