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Evaluate this research scenario to determine the appropriate statistical test and formulate the precise null and alternative hypotheses. Justify your choice based on the structure of the study.
Case context: A health psychologist investigates the accuracy of university students' estimates of the number of calories in a standard chocolate chip cookie. The actual number of calories in the cookie is 250. The psychologist collects calorie estimates from a sample of students and computes the sample mean ().
Question: Evaluate this research scenario to determine the appropriate statistical test and formulate the precise null and alternative hypotheses. Justify your choice based on the structure of the study.
Sample answer: The appropriate statistical test is a one-sample -test. This is justified because the study compares a single sample mean (, the students' average estimate) to a specific, known hypothetical population mean ( calories), which serves as a standard of comparison. The null hypothesis should be formulated as (meaning the population's true mean estimate equals the actual calorie count), and the alternative hypothesis should be formulated as (meaning the true population mean estimate differs from the actual count).
Key points:
- Selects the one-sample -test.
- Identifies the hypothetical population mean () as 250.
- Formulates the null hypothesis as .
- Formulates the alternative hypothesis as .
- Justifies the test by stating it compares a single sample mean against a specific standard of comparison.
Rubric: A full credit response correctly identifies the one-sample -test, accurately formulates the null and alternative hypotheses using 250 as , and justifies the choice by referencing the comparison of a single sample mean to a specific hypothetical standard.
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Research Methods in Psychology - 4th American Edition @ KPU
Related
Null Hypothesis
Alternative Hypothesis
Assumptions
Formula for the One-Sample t-Test
Dependent-Samples t-Test
Null and Alternative Hypotheses for the One-Sample t-Test
Degrees of Freedom (One-Sample t-Test)
Example of a One-Sample t-Test
What is the primary purpose of a one-sample t-test?
Match each component of the one-sample t-test to its correct description.
A cognitive psychologist is investigating whether the average reaction time of 50 video game players differs from the general population mean of 300 milliseconds. Arrange the following steps of a one-sample t-test in the correct logical order for this study.
A clinical psychologist is conducting a one-sample t-test to compare the average anxiety scores of patients in a new treatment program to a known population mean. If the psychologist observes that the standard deviation within the sample is larger than expected, while the difference between the sample mean and the population mean remains the same, the resulting t-statistic will be closer to zero.
A researcher conducts a one-sample -test to compare the mean stress scores of a sample of emergency room nurses () to the known general population average (). Despite obtaining a statistically significant result () due to a large sample size, the researcher evaluates the finding as having low practical importance because the calculated _____ was only , indicating a negligible magnitude of difference.
Based on the definition of a one-sample -test, which statistical values are compared in this procedure?
In a one-sample -test, the alternative hypothesis is formulated as , which states that the true population mean differs from the hypothesized value.
A health psychologist is investigating university students' accuracy in estimating the calories in a chocolate chip cookie (which actually has 250 calories). Match each element of this study to its corresponding role in a one-sample -test.
Analyze the structural relationship between the sample mean (), the hypothetical population mean (), and the competing hypotheses in a one-sample -test. How do these components work together to help researchers evaluate statistical evidence?
Evaluate this research scenario to determine the appropriate statistical test and formulate the precise null and alternative hypotheses. Justify your choice based on the structure of the study.
In the context of a one-sample -test, what specific standard of comparison is the single sample mean evaluated against, and how is the null hypothesis mathematically defined?