Data Analysis Problem

From the given data set, select a sample of 30 values and construct the 95% and 99% confidence intervals of the mean. Find the mean of all the values and determine if the confidence intervals contain the mean. State what sampling method you used.

Data Set VII Acreage Owned by 35 Municipalities in Southwestern Pennsylvania

The t Distribution table (Table F) can be found here: elementary-statistics-by-Bluman-8th-Edition (page 786 from the book OR 825 of 943 from the pdf).

ognamdik said:

From the given data set, select a sample of 30 values and construct the 95% and 99% confidence intervals of the mean. Find the mean of all the values and determine if the confidence intervals contain the mean. State what sampling method you used.

Data Set VII Acreage Owned by 35 Municipalities in Southwestern Pennsylvania

384	44	66	218	250
198	60	306	105	600
10	38	87	227	340
48	70	58	223	3700
22	78	165	150	160
130	120	100	234	1200
4200	402	180	200	20

The t Distribution table (Table F) can be found here: elementary-statistics-by-Bluman-8th-Edition (page 786 from the book OR 825 of 943 from the pdf).

Click to expand...

Please read the post titled "Read before Posting".

We can help - we only help after you have shown your work - or ask a specific question
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what if i use systematic sampling? i am confused as to how i will go about choosing the samples.
total population is 35 and required sample size is 30.
according to the book, in systematic sampling, i have to choose the first sample number randomly. so i have to use the table of random numbers. but the table of random numbers in the book has five digits each.
can i just choose, say for example, the 3rd number of the 1st column as starting point and get the 30 numbers from there?
10
48
22
130
4200
44
60
38
70
78
120
402
62
306
87
58
165
100
180
218
105
227
223
150
234
200
250
600
340
3700

Subhotosh Khan said:

Please read the post titled "Read before Posting".

We can help - we only help after you have shown your work - or ask a specific question
(not a statement like "Don't know any of these")

Please share your work with us indicating exactly where you are stuck -
so that we may know where to begin to help you.

Click to expand...

If you have access to a software called MS-Excel, you can use their randomnumber generator function RANDBETWEEN(a,b).

I'm wondering why a random number must be chosen from a book, in order to begin at a random position on the list.

Could we ask a roommate or call a friend and say, "Pick a number from 1 through 35, and tell me what it is".

If they pick 16, then begin with the 16th number on the list. Hey -- I just picked that number at random, so why can't you use it? :cool:

I don't remember most of my stats course, but I'm thinking that systematic sampling is not much more than coming up with some "system" of your own.

For example, if I wanted to choose 100 first names at random from a 1965 telephone book, I could simply decide to start with the bottom-left entry on page 16 and then continue collecting names from the bottom-left of every 27th page until I had 100 names. That's my system. I just made up the numbers 16 and 27.

Of course, if I were sampling random last names instead of first names, then my system would be terribly biased because my sample would be concentrated with names beginning with the same letter. So, systematic sampling cannot always be totally random. We need to consider bias.

Well, you don't have to use a book! Many calculators have "random number" buttons and computer languages have "random number" (although in both cases you can argue about just how good any algorithm can be at giving a true "random" number). If you wanted a random integer from 1 to 6, uniformly distributed, roll a die! And you can get dice with other numbers of sides for other random numbers (If I remember correctly the boxed "dungeons and dragon" set had a number of different sided dice).

However, tests have been made that show if you ask a person to "choose a number" in a given interval, they are more likely to give a number in the middle of the interval, not a "randomly chosen" number.