# [數學]統計問題

1.Before the presidential debates, it was expected that the percentages of registered voters in favor of various candidates to be as follows.

Percentages

Democrats48%

Republicans38%

Independent 4%

Undecided10%

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:

Number ofObserved

Emergency Calls (x)Frequency (f)

0 9

112

230

327

422

513

6 7

Total120

Use a = 0.05 and test to see if the above data have a Poisson distribution.

### 2 個解答

• 5 年前
最佳解答

1.

X^=8.18

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.

2.

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
• 5 年前

可以找易統計，專業的服務