QUESTION

# You are the quality assurance person working an assembly line at a TV manufacturing plant. They produce 1000 TV's a day.

#1. You are the quality assurance person working an assembly line at a TV manufacturing plant. They produce 1000 TV's a day.  IF THE TV'S ARE ALL THE SAME MODEL, WHAT PERCENTAGE (think about the cost of testing) WOULD YOU TEST (WHY?) AND HOW WOULD YOU SELECT THEM (Don't just say "randomly" - How do you do it randomly?) If the inspector were lazy, how would they likely do it as a "convenience" sample? Lastly, if the 1000 TV's were 4 different models, how would you sample then and what type of sampling would this be?

#2. You are going out to eat. There are three shopping malls nearby and each has up to five restaurants (these restaurants are all different styles: e.g., Italian, Chinese, French). Here are their customer SATISFACTION ratings on a scale of up to five +'s  (highest satisfaction).  WHAT ASSUMPTIONS ARE YOU MAKING REGARDING WHAT "SATISFACTION" MEANS?

Mall 1                         Mall 2                         Mall 3

(a) ++++                   (a) +++                     (a) +++++

(b) ++++                   (b) ++                        (b) ++++

(c) ++++                   (c) +++                      (c) +++

(d) ++                        (d) +

(e) +++

#3. (a) What type of data and scale are involved here?

(b) Which Mall Restaurant did you pick? WHY?

(c) What issues could you encounter with your pick once you got there?

#4. What is a CONVENIENCE SAMPLE? Give an example of one and explain when it might be actually useful in giving a picture of the entire population, and what could be misleading about it.

#5.  You can find 20 RANDOM NUMBERS in a Table or you can generate them with software like Excel. The Excel functions are "RAND" and "RANDBETWEEN". With "Randbetween" you simply input how many numbers you want, the number of digits you want in your random number and the range of values you want those numbers to fall between. For example you may want twenty, 2-digit numbers that fall between 00 and 100 (like "34").

TWO CONSIDERATIONS: (1) You must systematically use the random numbers in the Table or the ones generated. You don't "skip around" because that could un-randomize the values. (2) Let's say you want 1000 names from a 50 page phone book. You reach the end of the book with your systematic selection and only have 800 names. What do you do? Simple: start over in the book (loop). For example, if you were selecting names from every 15th page and you reached the end of the book after only 8 pages, then start over on page 7 of the same book.

One source of random numbers is the Greek symbol "π" and its numerical value used in geometry is 3.141592653589793238462643383. . . (ignore the decimal between 3 and 1) and you have THIS string of random numbers: 3141592653589793238462643383.

USE THIS STRING (and loop it) to generate twenty, 3-digit (e.g. 314) random numbers AND EXPLAIN how you did it.