Q1 （10分）
A problem with a phone line that prevents a customer from receiving or making calls is upsetting to both the customer and the telecommunications company. The file Phone contains samples of 20 problems reported to two different offices of a telecommunications company and the time to clear these problems (in minutes) from the customers' lines:
Central OfficeⅠTime to Clear Problems (minutes)
1.48 1.75 0.78 2.85 0.52 1.60 4.15 3.97 1.48 3.10 1.02 0.53 0.93 1.60 0.80 1.05 6.32 3.93 5.45 0.97
Central Office Ⅱ Time to Clear Problems (minutes)
7.55 3.75 0.10 1.10 0.60 0.52 3.30 2.10 0.58 4.02 3.75 0.65 1.92 0.60 1.53 4.23 0.08 1.48 1.65 0.72
Assuming that the population variances from both offices are equal, is there evidence of a difference in the mean waiting time between the two offices? (Use )
Q2 （10分）
A hospital conducted a study of the waiting time in its emergency room. The hospital has a main campus and three satellite locations. Management had a business objective of reducing waiting time for emergency room cases that did not require immediate attention. To study this, a random sample of 15 emergency room cases that did not require immediate attention at each location were selected on a particular day, and the waiting times (measured from check-in to when the patient was called into the clinic area) were collected and stored in ERWaiting.
At the 0.05 level of significance, is there evidence of a difference in the mean waiting times in the four locations?
Q3 （10分）
A metallurgy company wanted to investigate the effect of the percentage of ammonium and the stir rate on the density of the powder produced. The results (stored in Density ) are as follows:
At the 0.05 level of significance,
is there an interaction between the percentage of ammonium and the stir rate?
Q4 （9分/3小題各3分）
（題1）
假設身高與體重的母體迴歸線與母體分配關係如圖示，其中的(a)、(b)兩個交點（各自對應不同的身高、體重），所 代表的說明是什麼？請以圖示的數字說明兩個交點的含意：
(a) .
(b) .
（題2）
(a) R2 = 1 (b) 0 < R2 < 1 (c) R2 = 0
請填寫正確對應的判定係數
(Coefficient of Determination)
(1) 【 】
(2) 【 】
(3) 【 】
（題3）
判定係數 R2 可以是衡量迴歸方程式的解釋能力，其 方式是從觀測值與平均數的差距導出，從上圖中的 (1)、(2)、(3)中，請填入以下所代表的含意：
(1)【 】 (2)【 】 (3)【 】
(a)誤差 (b)可解釋誤差 (c)不可解釋誤差
