Homework Sourse1 For an independent samples study you have two randomly ass
1. For an independent samples study, you have two randomly assigned groups: a control group and a treatment group. The scores for the control group are 7, 5, and 3. The scores for the treatment group are 1, 4, and 7. The variance for the control group is 4.0 and the variance for the treatment group is 7.0.
What is the standard error of the difference between the means for this study? In other words, what is the value of the denominator for the independent-samples t-test?
Give an answer showing two places to the right of the decimal.
2. Subjects are tested for their ability to read emotional expressions on people\'s faces before and after a stress manipulation. The stress experience is expected to affect with their ability to correctly read facial expressions. The scores (dependent variable) indicate the number of correctly identified expressions.
Here are the scores before they are stressed: 10, 9, 8, 7, 7, 4, 4.
Here are the scores after they are stressed: 5, 7, 5, 6, 4, 5, 3.
Note that the order of subjects is the same in both lists, so 10 goes with 5, 9 goes with 7, and so on.
What is the value of the t-statistic for these subjects?
Report your answer as a positive number showing two places to the right of the decimal.
3.
| This question has the same data that you worked with in question 2, but the description has been changed to fit an independent-samples study. Subjects are tested for their ability to read emotional expressions on people\'s faces. Some people are tested without any manipulation, while a different group is tested after a stress manipulation. Assignment to the two conditions is random. The stress experience is expected to affect the ability of the subjects in the stress manipulation condition to correctly read facial expressions. The scores (dependent variable) indicate the number of correctly identified expressions. Here are the scores for the subjects in the control condition: 10, 9, 8, 7, 7, 4, 4. Here are the scores for the subjects in the stress condition: 5, 7, 5, 6, 4, 5, 3. What is the value of the t-statistic for these subjects? Report your answer as a positive number showing two places to the right of the decimal. |
Solution
1.
As
SE = sqrt(var1/n1 + var2/n2)
Here, var1 = 4, var2 = 7.0, n1=n2 = 3, then
= sqrt(4/3 + 7/3)
SE = 1.914854216 [ANSWER]
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