A clinical neuropsychologist develops a new treatment for recovery from head trauma and administers it to one half (randomly selected)of a sample of 50 people.He measures the level of cognitive functioning one month after the trauma and analyses the data in SPSS.The output of a between-participant t-test is shown below: Which of the following statements is true?
A)The test shows the treatment works.
B)The test shows the treatment works so long as we can rule out problems with internal validity.
C)The test shows the treatment works so long as we can rule out problems with internal validity and external validity (e.g., selection X treatment effects).
D)The test shows that the effects of the treatment are not due to chance.
E)The test provides us with good grounds to be confident that the observed difference is not due to chance.

Question

A clinical neuropsychologist develops a new treatment for recovery from head trauma and administers it to one half (randomly selected)of a sample of 50 people.He measures the level of cognitive functioning one month after the trauma and analyses the data in SPSS.The output of a between-participant t-test is shown below:  Which of the following statements is true?
A)The test shows the treatment works. 
B)The test shows the treatment works so long as we can rule out problems with internal validity. 
C)The test shows the treatment works so long as we can rule out problems with internal validity and external validity (e.g., selection X treatment effects). 
D)The test shows that the effects of the treatment are not due to chance. 
E)The test provides us with good grounds to be confident that the observed difference is not due to chance.

Quizplus · Accepted Answer

The output of the t-test provides us with a p-value of .025, which is less than the standard alpha level of .05. This means that there is less than a 5% chance that the observed difference in cognitive functioning between the treatment and control groups is due to chance. Therefore, we can be confident that the treatment has a significant effect on cognitive functioning. However, the t-test does not provide information about internal or external validity, so we cannot fully rule out those potential issues.

A Clinical Neuropsychologist Develops a New Treatment for Recovery from Head