PSYC4700 2023 January Week 8 Assignment Latest

PSYC4700 Statistics for the Behavioral Sciences

Week 8 Assignment  

Chi-Square Tests

Complete the following problems within this Word document. (Do not submit other files.) Show your work for problem sets that require calculations. Ensure your answer to each problem is clearly visible. (You may want to highlight your answer or use a different type of color to set it apart.)

Submit the document to your instructor by Sunday, 11:59 p.m. central time.

Problem Set 8.1: Critical Values

Criterion: Explain changes in critical value based on calculations.

Instructions: Read the following and answer the questions.

The chi-square table. The degrees of freedom for a given test are listed in the column to the far left; the level of significance is listed in the top row to the right. These are the only two values you need to find the critical values for a chi-square test.

Work through the following exercise and write down what you see in the chi-square table. This will help familiarize you with the table.

Increasing k and ? in the chi-square table

1.            Record the critical values for a chi-square test, given the following values for k at each level of significance:

                .10         .05         .01

k = 10    ___         ___         ___

k = 16    ___         ___         ___

k = 22    ___         ___         ___

k = 30    ___         ___         ___

Note: Because there is only one k given, assume this is a goodness-of-fit test and compute the degrees of freedom as (k − 1).

2.            As the level of significance increases (from .01 to .10), does the critical value increase or decrease? Explain. ___________________________________

3.            As k increases (from 10 to 30), does the critical value increase or decrease? Explain your answer as it relates to the test statistic. ___________________________________

Problem Set 8.2: Parametric Tests

Criterion: Identify parametric tests.

Instructions: Based on the scale of measurement for the data, identify whether a test is parametric or nonparametric.

1.            A researcher measures the proportion of schizophrenic patients born in each season. ___________________________________

2.            A researcher measures the average age that schizophrenia is diagnosed among male and female patients. ___________________________________

3.            A researcher tests whether frequency of Internet use and social interaction are independent. ___________________________________

4.            A researcher measures the amount of time (in seconds) that a group of teenagers uses the Internet for school-related and non-school-related purposes. ___________________________________

Problem Set 8.3: Chi-Square Analysis in JASP

Criterion: Use JASP for a chi-square analysis.

Data: Use the Yummy data set. Tandy’s ice cream shop serves chocolate, vanilla, and strawberry ice cream. Tandy wants to plan for the future years. She knows that on average she expects to purchase 100 cases of chocolate, 75 cases of vanilla, and 25 cases of strawberry (4:3:1). This year, she purchased 133 cases of chocolate, 82 cases of vanilla, and 33 cases of strawberry. The Yummy data set is a record of ice cream sales this year.

Instructions: Complete the steps below.

1.            Download Yummy data set. Double-click the icon to open the data set in JASP.

2.            In the Toolbar, click Frequencies. In the menu that appears, under Classical, select Multinomial Test.

3.            Select Flavor and then click the upper Arrow to send it over to the Factor box.

4.            Select Frequency and then click the lower Arrow to send it over to the Counts box.

5.            Click the circle next to Expected Proportions (χ2).

6.            Fill in 4 for Chocolate, 1 for strawberry, and 3 for Vanilla.

7.            Select the box for Descriptives and click the circle next to Proportions.

8.            Copy and paste the output to the Word document.

9.            Answer this: Was Tandy’s distribution of proportions the same as expected?