Answers to Homework for Chapter 3

3.6	Starting with 01 and numbering down the columns, one chooses 19-Laskowsky, 26-Rodriguez, 05-Castillo, 09- Gonzales

3.8	Assign 01 to 30 to the students (in alphbetical order).  The exact depends on which line one choses in Table B;

3.12	Form A would draw the higher negative response.  It is phrased to do so.  Form B presents both sides of the issue.

3.13  The increased sample size gives more accurate information about the population

3.17	The call-in poll is faulty in part because it is a voluntary sample.  Furthermore, even a small charge like 50 cents can discourage some people from calling in; especially poor people. 

3.19	Number the bottle across the rows from 01 to 25, then select 12-B0986, 04-A1101, and 11-A2220.  

3.20	The blocks are already marked; select three-digit numbers and ignore those that do not appear on the map.  THis gives 214, 313, 409, 306, and 511.

3.23	It is *not* and SRS.  In order to be a SRS, everypossible sample of 250 must have an equal chance of being chosen (For example, a group of 250 female engineers will not be picked).

3.28	(a) Experiment, where the treatment is the instruction method.  (b) THe expanitory variable is the method used (computer or standard), and the response is the change in reading ability.

3.31

3.32 (a) Randomly select 20 women from group 1, which will see ther "childcare" version of Company B's brochure, and assign the other 20 women to Group 2 (the "no childcare group).  Allow all women to examine the appropriate brochures and observe which company they choose.  Compare the number from Group 1 who choose Company B with the corresponding number number from group 2. (b) Numbering from 01 to 40, Group 1 is 05-Cansisco, 32-Roberts, 19-Hwang, 04-Brown, etc.

3.33 Number the liners from 01 to 20 then take Group 1 to be 16,04,19,07 and 10.  Gorup 2 is 13, 15, 05, 09, and 08; Group 3 is 18,03,01,06,11.  The others are Group 4

3.34	Randomly assign 6 students too each of Groups 1,2,3,4,5 and 6.