are examples of kinds of graphs.

What you have learned is indicated in the report, especially the Introduction and the Conclusion. You should begin the Introduction by setting up the learning context, which is the scientific concept that forms the foundation of the lab. This is what you are supposed to be learning about in the lab. Be sure that the learning context you establish in the Introduction does indeed match the learning context from the lab manual or handout.

Formally we do not reject the null hypothesis.

Example: A random sample of rats receives daily doses of alcohol during pregnancy.

Formally we reject the null hypothesis.

Different fields tend to have different styles of documentation, that is, the way you cite a source and the way you represent the source in the References. For example, biologists use the documentation style of the Council of Biological Editors, and chemists use the style of the American Chemical Society. If you don't know what style you are expected to use in your reports (it's often given in the lab manual, check with your lab instructor. For further help you can check LabWrite Resources, "Citations and References."

There are four steps involved in hypothesis testing:

If you think you need to do more to convince your reader that you have learned what you say you have learned, provide more details in the Conclusion. For example, compare what you know now with what you knew before doing the lab. Describe specific parts of the procedure or data that contributed to your learning. Discuss how you may be able to apply what you have learned in the lab to other situations in the future.

Example: We compare the observed mean birth weight with the hypothesized values of 18 grams.

failing to reject the null hypothesis when it is false.

The experimental results don't look different than we expect according to the null hypothesis, but they are, perhaps because the effect isn't very big.

failing to reject the null hypothesis when it is true.

1-state what the lab is about, that is, what scientific concept (theory, principle, procedure, etc.) you are supposed to be learning about by doing the lab. You should do this briefly, in a sentence or two. If you are having trouble writing the opening sentence of the report, you can try something like: "This laboratory experiment focuses on X…"; "This lab is designed to help students learn about, observe, or investigate, X…." Or begin with a definition of the scientific concept: "X is a theory that…."

rejecting the null hypothesis when it is true.

2. give the necessary background for the scientific concept by telling what you know about it (the main references you can use are the lab manual, the textbook, lecture notes, and other sources recommended by the lab manual or lab instructor; in more advanced labs you may also be expected to cite the findings of previous scientific studies related to the lab). In relatively simple labs you can do this in a paragraph following the initial statement of the scientific concept of the lab. But in more complex labs, the background may require more paragraphs.

Specifically, we identify the mean we expect if the null hypothesis is true.

the null hypothesis is not rejected when it is false c.

In many disciplines, professors may discourage the adoption of a single template for writing assignments. However, in psychology, formal papers are usually required to follow APA format. Below is an overview of how to specifically format lab reports for Intro to Psychology lab classes, but a more in-depth discussion of formatting papers in APA style is located here. The lab report follows the same basic "hourglass" structure as an empirical journal article (without the abstract):

The experimental results look really different than we expect according to the null hypothesis.

the result would be unexpected if the null hypothesis were true c.

This proce- dure can be viewed as a test of the hypothesis p = .05 against the alternative p > .05, p being the probability that the machine turns out a defective item.

If we decide that they are significantly different, we reject the null hypothesis that .

Test the appropriate hypothesis at the 5% level.


To establish the scientific concept for the lab you need to do two things:

1. state what the lab is about, that is, what scientific concept (theory, principle, procedure, etc.) you are supposed to be learning about by doing the lab. You should do this briefly, in a sentence or two. If you are having trouble writing the opening sentence of the report, you can try something like: "This laboratory experiment focuses on X "; "This lab is designed to help students learn about, observe, or investigate, X ." Or begin with a definition of the scientific concept: "X is a theory that ."