Assignment
Create a scenario where the binomial probability formula could be used to determine the probability of some number of successes, x, in some given number of trials, n. Base your scenario on a situation that you might be familiar with, for example, at work or at school. Start with a paragraph of text describing your scenario and the variable involved, and then complete the following:
1. Describe the possible outcomes of a set of trials involving this variable, and explain why it can be described as a binomial experiment. (5 points)
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2. Assign values for p and q, suggest possible values for x and n in a hypothetical set of experimental trials, and calculate the probability of x successes in n trials given those values. Show all work. (5 points)
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Psychological tests are often standardized. This means the administration is consistent, and test administrators can use published norms to score the results (i.e., an individual’s results can be compared to the normative data, which represents the population as a whole, and that individual’s scores can be summarized and reported in terms of how they compare to the population from which the normative data was collected).
An example often used in psychology textbooks is the Wechsler Adult Intelligence Scale (WAIS), often referred to as an IQ test. The WAIS has a normative mean of 100 and a standard deviation of 15 points. Any person’s score on the WAIS can be summarized in various ways, for example, as the distance from the mean, or in terms of quartiles or percentiles.
Use the Assessment Psychology Online website, or conduct an Internet search to identify another behaviorally oriented standardized test (i.e., not the WAIS), and respond to the following:
1. Start with a general description of the instrument, including who developed it, its intended purpose, and how it is administered. (3 points)
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2. Describe the normative data (i.e., the mean, standard deviation, and any other relevant parameters). (3 points)
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3. What would be the probability of a person chosen at random from the population scoring more than 1.0 standard deviation above or below the mean? (2 points)
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4. Describe, in behavioral terms, what a z-score of 1.0 represents. (2 points)
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In Chapter 6, you’ve learned how to construct confidence intervals for population parameters and proportions, based on data from samples.
Respond to the following to describe a “real world” scenario where a researcher might want to construct a confidence interval to support a conclusion about a population parameter.
1. Provide an overview of the scenario and the variable involved. Include an explanation of why and how constructing the confidence interval adds value. I.e., why might this information be important to know? (4 points)
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2. Identify any assumptions that must be met. (3 points)
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3. Describe an overview of the process of constructing the confidence interval along with the steps involved. (3 points)
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