Honors IS Lab- the t-test

Today in lab I introduced you to the t-test, showed you how to conduct a t-test on Excel to compute the p-value, and finally how to use the p-value to help you correctly evaluate your hypotheses. Although I think that people were getting a hang of what was going on by the end of lab, my experience tells me that unless you sit down and think deeply about the material before next week that you will be unlikely to master the material. As I mentioned today, there will be a midterm testing your knowledge of the statistical tests. I think it would be helpful for you to get some practice answering the types of questions that you will be required to answer on the exam.

1. When do you use a t-test to help test your hypotheses?

2. Why do you use a t-test to help test your hypotheses?

3. Give an example of a question that needs to be answered using a two-tailed, paired t- test. (be sure to state the Ha and Ho and how you will collect the data)

4. Give an example of a question that needs to be answered using a one-tailed, unpaired t-test. (be sure to state the Ha and Ho and how you will collect the data)

5. Scientists is interested in knowing whether adding insecticides to a cotton field increases cotton yield. In several fields they spray insecticide on the fields and in several fields they do not add insecticides (the control plots).

Q. What statistical test should the scientists do to help answer their question?

6. Scientists are interested in knowing whether there is a difference in the male and the female students with the top GPAs in a univesity. They collected their data by examining the GPAs of the top male and female students at Texas Tech, Texas A&M, UT, and 12 other universities in Texas.

Q. What statistical test should the scientists do to help answer their question?

7. John, a new third grade teacher, noticed that his male students seemed to need to leave the class the restroom more often than did his female students. He decided to see if male students in his class peed on average more often each week than female students. For four weeks he counted the number of time that each student was excused from class to go the the restroom. What statistical test should John use to analyze his data?

(a) one-tailed, paired t-test
(b) one-tailed, unpaired t-test
(c) two-tailed, paired t-test
(d) two-tailed, paired t-test
(e) John does not need to use statistics to answer his question.

8. A scientist was interested in testing whether the grapefruit diet (eating only grapefruits for three months) or the doughnut diet (eating only doughnuts for three months( resulted in greater weight loss. Researchers located 30 volunteers and randomly assigned half of them to each diet. After three months the researchers determined the amount of weight lost by each participant. Here is the data-

weight loss (lbs)

Grapefruit Diet

5
4
3
5
2
1
3
0
5
7
5
3
9
2
4

Doughnut Diet

1
2
2
3
1
4
2
5
1
2
3
1
3
2
1

Follow all of the steps of the hypothesis testing protocol to determine which diet was most effective (make sure you write down all of the steps of the hypothesis testing protocol).

Something Silly from "The Onion"

Kansas Outlaws Practice of Evolution

http://www.theonion.com/articles/kansas-outlaws-practice-of-evolution,2098/

Oklahoma Doesn't Want to Be Left Out

Oklahoma is also considering new legislation.

JANUARY 23, 2012, 11:38 AM- The Wall Street Journal

A ‘Critique’ of Evolution Proposed in Oklahoma

If it seems like we keep hearing about the fight over teaching evolution in schools and teaching creationism, we do. It comes up like clockwork, despite the Scopes Monkey Trial of 1925.

Oklahoma is the latest state to breach the subject, but the language of the proposed law is different, even if, as critics suspect, the goal is the same. According to the National Center for Science Education, Oklahoma Senate Bill 1742 is the sixth anti-evolution bill introduced in 2012, following bills in New Hampshire, Missouri and Indiana.

The bill purports to recognize “the importance of critical thinking, logical analysis and objective discussion,” and directs schools to include “a scientific critique of the theory of evolution,” but maintains that its purpose is not to teach creationism or intelligent design, and not to promote any religious doctrine or set of religious beliefs.

The model for the bill, which is stated explicitly in it, is the Louisiana Science Education Act, which was passed in 2008, and is part of so-called “academic freedom” laws. Louisiana’s bill was opposed by every scientific society that took a position on it.

Oklahoma’s bill would cover discussion of evolution, the origin of life, global warming, and human cloning. It states that teachers would use standard scientific text books, and supplement lessons with additional texts and “instructional materials.” Section 5 of the bill declares that an “emergency” exists, and for the “preservation of public peace, health and safety,” the provisions of the bill would go into effect immediately upon passage and approval. The bill can be read in full on the NCSE website.

A study published last year found that only 28% of biology teachers follow the National Research Council’s recommendations to describe evolution in a straightforward manner and explain the ways in which it is a unifying part of all biology, the New York Times reported.

The study, which was called “Defeating Creationism In The Courtroom, But Not In The Classroom,” found that 13% explicitly advocate creationism, despite federal courts consistently holding such practice unconstitutional. The rest — “the cautious 60%,” as the study calls them — avoid controversy by not endorsing evolution or intelligent design.

And in New Hampshire as Well

I am putting links to these articles because they have been in the news recently. I look forward to hearing your comments on this.

New Hampshire’s 2012 anti-evolution legislation (and the shocking thing a sponsor said).

The link from this article in the Washington Post wasn't working so I will post the entire article.


New Hampshire’s 2012 anti-evolution legislation (and the shocking thing a sponsor said)
By Valerie Strauss
You can’t make up this stuff: The chief sponsor of a new anti-evolution piece of legislation in New Hampshire said that Darwin’s theory is “godless” and that such thinking is linked to Nazi atrocities, the 1999 Columbine shootings and more.

That analysis came from Republican Rep. Jerry Bergevin, who introduced one of two new anti-evolution bills (see below for full text of bills) in the Granite State’s legislature.

His House Bill 1148 would require that evolution is “taught in the public schools of this state as a theory, including the theorists’ political and ideological viewpoints and their position on the concept of atheism.”

Why?

Bergevin was quoted as saying this in the Concord Monitor:

“I want the full portrait of evolution and the people who came up with the ideas to be presented. It’s a worldview and it’s godless. Atheism has been tried in various societies, and they’ve been pretty criminal domestically and internationally. The Soviet Union, Cuba, the Nazis, China today: they don’t respect human rights.”

And this: “As a general court we should be concerned with criminal ideas like this and how we are teaching it. . . . Columbine, remember that? They were believers in evolution. That’s evidence right there.”

Leaves you speechless, doesn’t it?

The second piece of New Hampshire legislation, House Bill 1457, would require science teachers “to instruct pupils that proper scientific inquire [sic] results from not committing to any one theory or hypothesis, no matter how firmly it appears to be established, and that scientific and technological innovations based on new evidence can challenge accepted scientific theories or modes.”

In other words, the sponsors, Republican Reps. Gary Hopper and John Burt, want creationism taught in public schools right along with evolution.

That thinking ignores the overwhelming scientific consensus on the validity of evolution and tries to equate biology’s animating principle with creationist theory, which the science establishment rejects. (But why let science get in the way?)

Hearings on both bills are scheduled to be held in February.

The New Hampshire legislation are the first new anti-evolution bills introduced in any state in 2012 so far, according to the National Center for Science Education, a non-profit membership organization that defends the teaching of evolution in public schools.

Last year there were at least nine anti-evolution bills in seven states but none became law; at least one was postponed for considering this year. Many of those bills cited “academic freedom,” the idea that teachers should have the freedom to teach creationism and evolution equally.

The issue is important, especially at a time when most high school biology teachers are reluctant to endorse evolution in class, according to a 2011 poll conducted by Penn State political science professors Michael Berkman and Eric Plutzer and published in Science magazine:

*About 28 percent consistently implement National Research Council recommendations calling for introduction of evidence that evolution occurred, and craft lesson plans with evolution as a unifying theme linking disparate topics in biology.

* About 13 percent of biology teachers “explicitly advocate creationism or intelligent design by spending at least one hour of class time presenting it in a positive light.”

* The rest, about 60 percent, “fail to explain the nature of scientific inquiry, undermine the authority of established experts, and legitimize creationist arguments.”


Here are the two new New Hampshire bills:

HOUSE BILL 1148

AN ACT requiring the teaching of evolution as a theory in public schools.

SPONSORS: Rep. Bergevin, Hills 17

COMMITTEE: Education


ANALYSIS

This bill requires evolution to be taught as a theory in public schools.


STATE OF NEW HAMPSHIRE

In the Year of Our Lord Two Thousand Twelve

AN ACT requiring the teaching of evolution as a theory in public schools.

Be it Enacted by the Senate and House of Representatives in General Court convened:

1 New Paragraph; Duties of the State Board of Education. Amend RSA 186:11 by inserting after paragraph XXXVI the following new paragraph:

XXXVII. Theory of Evolution. Require evolution to be taught in the public schools of this state as a theory, including the theorists’ political and ideological viewpoints and their position on the concept of atheism.

2 Effective Date. This act shall take effect 60 days after its passage.

--

And here is the text of HOUSE BILL 1457

HOUSE BILL 1457

AN ACT relative to scientific inquiry in the public schools.

SPONSORS: Rep. G. Hopper, Hills 7; Rep. Burt, Hills 7

COMMITTEE: Education


ANALYSIS

This bill requires instruction in the proper methods of scientific inquiry.

STATE OF NEW HAMPSHIRE

In the Year of Our Lord Two Thousand Twelve

AN ACT relative to scientific inquiry in the public schools.

Be it Enacted by the Senate and House of Representatives in General Court convened:

1 New Paragraph; Duties of the State Board of Education. Amend RSA 186:11 by inserting after paragraph XXXVI the following new paragraph:

XXXVII. Scientific Inquiry. Require science teachers to instruct pupils that proper scientific inquire results from not committing to any one theory or hypothesis, no matter how firmly it appears to be established, and that scientific and technological innovations based on new evidence can challenge accepted scientific theories or modes.

2 Effective Date. This act shall take effect 60 days after its passage.

-0-

By Valerie Strauss | 04:00 AM ET, 01/06/2012

Indiana Passes Law Allowing Teaching of Creationism in Science Classes

Indiana Creationism Bill Passes the Senate

http://ncse.com/news/2012/01/indiana-creationism-bill-passes-senate-007182