AP Statistics Chapter 4 - Designing Studies

Observational studies

________ often fail to provide valid causal links between variables due to confounding The Language of Experiments A specific condition applied to the individuals in an experiment is called a treatment.

subset of individuals

 A sample is a(n) ________ in the population from which we actually collect data.

systematic pattern

 A(n) ________ of incorrect responses in a sample survey leads to response bias.

experimental units

The ________ are the smallest collection of individuals to which treatments are applied.

Forms of Bias

________ in Surveys and Samples  Undercoverage occurs when some members of the population can not be chosen in a sample.

 Chance

________ is used to determine which unit in each pair gets each treatment.

 Nonresponse

________ occurs when an individual chosen for the sample cant be contacted or refuses to participate.

Statistical Significance

________  An observed effect so large that it would rarely occur by chance is called statistically significant.

significant association

 A statistically ________ in data from a well- designed experiment does imply causation.

observational study

The distinction between ________ and experiment is one of the most important in statistics.

Random Digits A table of random digits is a long string of the digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 with these two properties

1

Step 2

Table

4.2

Experiments Observational Study vs Experiment  An observational study observes individuals and measures variables of interest but does not attempt to influence the responses

Principles of Experimental Design The basic principles for designing experiments are as follows

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