Question

A physical therapist conducts a study examining the effect of implementing a group exercise program at an assisted living facility for elderly adults. One group of residents is selected to participate in the program, and a second group serves as a control. After 6 weeks, the researcher records a combined score measuring balance and strength for each individual. The data are as follows:                          

     Control               Exercise

                                                 n = 10                 n = 15

                                               M = 12               M = 15.5

                                              SS = 120.5        SS = 190.0

If the researcher decides to use a two-tailed test at an α = .05 level, what are degrees of freedom and t_critical value?

		df = 23; tcrit = ±2.069
		df = 25; tcrit = ±2.060
		df = 5; tcrit = ±2.571
		df = 23; tcrit = ±1.714

Construct a 95% confidence interval for the difference in sample means to estimate the difference in population means.

		95% CI = 0.40 to 6.6
		95% CI = 10.43 to 18.07
		95% CI = 5.67 to 7.76
		95% CI = 0.93 to 6.07

Answer 1

from above:

df = 23; t_crit = ±2.069

95% CI = 0.40 to 6.6