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Zach Wahls To Co-Chair 'Outspoken Generation,' Gay Parents' Initiative For Adult Children, With Ella Robinson (Huffington post)

The Iowa student whose impassioned pro-gay marriage speech to Iowa legislators
became the most-watched political clip of 2011 on YouTube after going viral
twice last year will soon take his message to the national level.

Zach Wahls will serve as co-chair for "The Outspoken Generation," the Family
Equality Council's national youth advocacy initiative involving the young
adult children of LGBT parents. Joining him will be Ella Robinson, the
daughter of Bishop Gene Robinson who is the first openly gay person to be
ordained a bishop in a major Christian denomination.

"A family is a group of people who love each other," Wahls -- whose new book,
"My Two Moms," will be released later this month -- says in a video clip about
the project. "If you're willing to put in the blood, sweat, toil and
tears...if you're willing to make the commitment and demonstrate the love that
it takes to successfully raise a young, healthy, well-rounded adult...who you
are is so much less important than what you do."

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Huffington post

Standard Deviation, Precision and Mixtures.?

I need help with this problem i have been trying to figure it out but had no success, this is from chapter one of my AP Chemistry book:

Two students determine the percentage of lead in a sample as a laboratory exercise. The true percentage is 22.52%. The student's results for three determinations are as follows:
1. 22.52, 22.48, 22.54
2. 22.64, 22.58, 22.62
Precision can be judged by examining the average of the deviations from the average value for that set of data set. (Calculate the average value for each data set, then calculate the average value of the absolute deviations of each measurement from the average.) Which set is more precise?

Also, Suppose you are given a sample of a homogeneous liquid. What would you do to determine whether it is a solution or a pure substance?

I know that a pure substance has a uniform composition and a solution has more than one compound or element. So would chromatography work for this?

Any help will be appreciated. Thanks!

For the first question it's just saying this:
Average (set 1) = (22.52 + 22.48 + 22.54) / 3 = 21.513333
Deviation of 22.52 from (A1 = Average of set 1) = 22.52 -21.533

Then you take those differences and find the average and the smaller of the two sets is more precise. As the measurements of the set were better centered around their average.

For the second one I don't know.