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?

Power can range from -1 to +1.

At what level of significance are type 1 errors more likely?

A researcher developed an intervention designed to increase the grip strength of adults 85 years or older.  The researcher randomly selected 16 older adults and used available body mass index (BMI) data, to create 8 matched pairs on BMI. Within each pair, the researcher randomly assigned 1 participant to the intervention and 1 to the control group. The strength training program was implemented for 10 weeks (1 training session/week).  Immediately following the intervention, all adults were tested for grip strength.  Higher scores represent greater grip strength. What effect will increasing the number of matched pairs (instead of 8 pairs having 80 pairs) have on statistical power?

Is it appropriate to calculate a median for ordinal data?

An assumption underling the independent t-test is that the sample sizes are equal.

A researcher was interested in examining the effects of the daily amount of creatine (5 grams, 10 grams, 15 grams, 20 grams) on the 50-yard sprint time of 200 female runners who volunteered for the study. From these 200 participants, 50 participants were randomly assigned to a daily dose of 5 grams of creatine; 50 participants were randomly assigned to a daily dose of 10 grams of creatine; 50 participants were randomly assigned to a daily dose of 15 grams of creatine; and 50 participants were randomly assigned to a daily dose of 20 grams of creatine. After being on the creatine dosage for 2 weeks, each participant’s 50-yard sprint time was measured. What statistical technique would you use to examine the effects of the daily amount of creatine on sprint time? 

A researcher was interested in examining the effects of the daily amount of creatine (5 grams, 10 grams, 15 grams, 20 grams) on the 50-yard sprint time of 200 female runners who volunteered for the study. From these 200 participants, 50 participants were randomly assigned to a daily dose of 5 grams of creatine; 50 participants were randomly assigned to a daily dose of 10 grams of creatine; 50 participants were randomly assigned to a daily dose of 15 grams of creatine; and 50 participants were randomly assigned to a daily dose of 20 grams of creatine. After being on the creatine dosage for 2 weeks, each participant’s 50-yard sprint time was measured. What is the independent variable?