# failed exam on sampling..can you help?

• Jun 25th 2008, 06:34 AM
leaaa
failed exam on sampling..can you help?
Hi

I failed my data analysis exam and this question was one of many that I got wrong..

A 2% random sample of mail-order customers, each with a numeric serial number, is to be selected. A random number between 00 and 49 is chosen and turns out to be 14. Then customers with serial numbers 014, 064, 114, 164, 214 … are chosen as the sample.

(a)State the sampling frame for this survey.
(b)Name the type of sampling described above.
(d)Explain why the random number ‘14’ was chosen first.

Would be nice to know where i went wrong, can anyone answer this for me so i can compare my notes?
• Jun 25th 2008, 06:35 AM
leaaa
i got (a) Simple random sampling
• Jun 25th 2008, 08:16 AM
TKHunny
Note: Some people simply ignore posts that have been answered. When you answer your pown post, this may become very confusing.

Why would it be a simple random sample? Perhaps this is correct for the first group of 50. 1/50 = 2%, by the way, and this answers part D.

If your numbers are listed 50 per page, you will get one from each page. This is a good thing. Perhaps that could be called Stratified?

If your people live in little groups of 50, you will be picking the 14th one from each group. This is neither random nor advantageous.

What other choices have you for "Type of Sampling"?

Controlled?
Grouped?
Not Random?
Others?