A researcher was interested in evaluating an intervention that would impact body mass. The researcher was also interested in evaluating if there were sex differences in body mass. The researcher recruited 10 males and 10 females for the study. For the 10 males, 5 males were randomly assigned to the intervention and 5 males were randomly assigned to a control condition. Similarly, for the 10 females, 5 females were randomly assigned to the intervention and 5 females were randomly assigned to a control condition. Based on the information provided, what type of research design was used in this study?

5 older adults volunteered for a study interested in determining the strength of older adults. The 5 older adults were asked to do as many pull-ups as they could. The number of pull-ups for the 5 participants is listed below.  The pull-up results (X) were: 5, 2, 2, 7, 9 What is the variance for the number of pullups?    

A researcher was interested in comparing 3 group conditions: Meditation, Progressive Relaxation, and a Control condition on heart rate. 28 freshmen undergraduates from USF were randomly selected.  From these 28 students, 13 were randomized to the Control Condition, 8 were randomly assigned to Meditation, and 7 were randomly assigned to Progressive Relaxation. What would be the degrees of freedom for: Between groups df = _____  

A researcher developed an intervention designed to increase the strength of adults 85 years or older.  The researcher randomly selected 6 older adults, pretested the adults to determine their pre-intervention strength, implemented the strength training program for 10 weeks (1 training session/week), and then posttested them immediately following the last intervention session.  Higher scores represent greater strength. If the researcher calculated a t-ratio of 2.62 (p=.024) and used a .05 level of significance, what conclusion should the researcher make?

What effect will increasing the sample size have on the width of the confidence band around the estimated parameter?

The computed t-ratio from an independent t-test will always be positive. 

Is it possible to have a z-score of 1.0 and a percentile rank of 45?

A researcher compared the mean number of risk factors for male and female undergraduate students.  What statistical technique would be most appropriate for this situation?

Where would the ecological validity of a research study be stronger?

A researcher was interested in evaluating if there was a relationship between participants’ weight and their vertical jumping score measured in inches.  What statistic would you use?