AD AGENCIES are interested in knowing the population percent (proportion) of women who make the majority of CAR BUYING decisions. If you were designing this study to determine this population proportion, what is the minimum number (N) you would need to survey to be 95% confident that the population proportion is estimated to within 5% (0.05)?

1. THIS IS A z-VALUE PROBLEM (NOT t-VALUE)

2. WHAT IS THE FORMULA WE USE TO FIND "n" ?

3. WHAT ARE THE VALUES FOR P' AND Q' (HINT: THIS IS A BINOMIAL SITUATION: MALE/FEMALE SO ASSUME 50:50 OR 0.5 AND 0.5)

4. WHAT ARE THE VALUES OF EBP AND EBP²?

5. WHAT ARE THE VALUES OF AND / 2 ?

6. USING THE z-TABLES (NOT THE t-TABLES) WHAT IS THE z-VALUE FOR THIS / 2 ?

7. PLUG THESE VALUES INTO THE FORMULA FOR "n" AND YOU GET n = _________

(YOU CAN REFER TO ILLOWSKY PAGE 447 FOR OTHER GUIDANCE)