Question

To prepare for this Assignment, imagine that you have information about how 20 nursing students and 20 psychology students felt about starting PSYC 3002 on Day 1 of this class. You want to know if nursing students and psychology students felt differently about embarking on the Introduction to Basic Statistics journey. You can find the data set for this Assignment in the Weekly Data Set forum found in the Discussions area of the course navigation menu.

Nursing	Psychology
Nervous	4	11
Excited	16	9

Another way of looking at this data set would be:

4 Nervous Nursing Students

11 Nervous Psychology Students

16 Excited Nursing Students

9 Excited Psychology Students

By Day 7

To complete this Assignment, submit your answers to the following. Use SPSS to determine if academic program is related to feelings about PSYC 3002 by computing the appropriate chi square test.

1. Recall the four scales of measurement you learned about in Week 1 (i.e., nominal, ordinal, interval, ratio). Explain what scale of measurement is used to measure academic program in this example. How do you know?
2. Explain what scale of measurement is used to measure feeling about PSYC 3002. Explain how you know.
3. State whether this scenario requires a goodness of fit test or a test of independence. Explain your answer.
4. Before computing the chi square, state the null hypothesis and alternative hypothesis in words (not formulas).
5. Identify the obtained χ2 using SPSS and report it in your answer document.
6. State the degrees of freedom and explain how you calculated it by hand.
7. Identify the p value using SPSS and report it in your answer document.
8. Explain whether you should retain or reject the null hypothesis and why.
9. Are the results statistically significant? How do you know?
10. Explain what you can determine about the relationship between academic program and feelings about PSYC 3002.

Answer 1

Our objective, here, is to test the claim whether nursing students and psychology students felt differently about embarking on the Introduction to Basic Statistics journey. If this was not the case, we would expect equal no. of nursing and psychology students to feel nervous / excited.

We would have enough evidence to prove otherwise if the observed counts differ significantly from expected counts.

To test:

There is no significant dependence between Major (subject) chosen by students and their response on Basic statistics (Or)   

Vs

There is a significant dependence between Major (subject) chosen by students and their response on Basic statistics (Or)   

Using SPSS,

We get the Output:

1.The data can be entered in the form of 1's and 2's (representing the categories for the two variables) and then coding the values using value labels:

Clicking on the value label A - 1 in the tab, we get the labels in the data view.

Recalling the four scales of measurement (i.e., nominal, ordinal, interval, ratio), since, both the variables 'Academic Program' and 'Feeling' are both categorical in nature, they are measured in nominal scale with distinct categories.The scale of measurement used to measure academic program in this example is nominal, since the observations are nothing but counts of students who belong to either of its distinct categories- Nursing or Psychology.

2. The scale of measurement used to measure feeling about PSYC 3002 is again nominal since the observations are nothing but counts of students who belong to each of its distinct category- Nervous or Excited.

3. This scenario requires a test of independence because our objective here, is to test if academic program is dependent on / affects the measure of feeling about PSYC 3002.

4. The null hypothesis and alternative hypothesis can be stated in words as:

There is no significant dependence between Academic Program chosen by students and their Feeling on Basic statistics (or)   Academic Program chosen & Feeling on Basic statistics are independent.

Vs

There is a significant dependence between Academic Program chosen by students and their Feeling on Basic statistics (or) Academic Program chosen & Feeling on Basic statistics are dependent.

5. From the SPSS output obtained, the Pearson's chi square statistic has the value 5.227

6. From the SPSS output obtained, the degrees of freedom, is 1. It can be obtained using the formula: (No. of Rows - 1)(No. of Colmns - 1) = (2-1)(2-1) = (1)(1) = 1 degree of freedom.

7. The p value obtained is 0.022. It is the probability of obtaining a result as extreme as the one obtained, when the null hypothesis is true.  

8. Based on the p- value obtained above, since the chance of obtaining a result as extreme as the one obtained, when the null hypothesis is true is very low (0.022 < 0.05) at say, 5% level of significance; chance of the null hypothesis being true is low. We may reject H₀ at 5% level.

9. We may conclude that the result is statistically significant. Since, the result deviates significantly from the null.

10. Regarding the relationship between academic program and feelings about PSYC 3002, we may conclude that the two study variables are dependent. Based on this sample data, we may infer that nursing students and psychology students felt differently about embarking on the Introduction to Basic Statistics journey.