Question

What is the dependent t-test score for these two group? Is there a sig. diff. between these two groups at alpha.05 (two-tailed) Alternative hypothesis (H1), degrees of freedom, T-crit, and interpretation of results (conclusion) *Determine the EFFECT SIZE* and give the intepretation. USE THE AVG. of the TWO STD. DEV Subjects Group 1 Group 2 2 2 10

Answer 1

It is given that we need to use dependent t test. Let d= group1 -group 2

Following table shows the calculations:

Group 1	Group 2	d=before-after	(d-mean)^2
5	6	-1	0.3025
4	2	2	12.6025
5	8	-3	2.1025
6	7	-1	0.3025
3	4	-1	0.3025
4	7	-3	2.1025
5	6	-1	0.3025
4	8	-4	6.0025
4	6	-2	0.2025
5	7	-2	0.2025
7	8	-1	0.3025
Total		-17	24.7275

Sample size n 11 Sample sum of difference: ean of differences: Sample m Sample standard deviation of differences: sqrt(24.7275/(11-1)) n-1 1.5725

Hypotheses are H, Level of significance α 0.05 Test is two tailed Degree of freedom: df -n-1-10 Test Statistics: t =(-1.55-0)/(1.5725/sqrt(11)) 7 -3.27 Critical value: 2.228 If |t| >2.228, Reject HO Rejection Region: Decision: Since test statistics lies in rejection region so we reject the null hypothesis P-value P-value-0.0084 Decision: Since p-value is less than level of significance so we reject the null hypothesis Excel function for critical value: Excel function for p-value =TINV(0.05,10) =TDIST(3. 27,10,2)

The effect size is

$Cohen's \text{ d}=\left |\frac{d-\mu_{d}}{s_{d}}\right |=0.99$

It is large effect size.