homework lab

lab_7.docx

Home >Mathematics homework help >homework lab

Lab 7

Problem: A researcher uses a repeated-measures study to examine the effectiveness of a therapy procedure for treating depression. A sample of n = 8 depressed patients is obtained and each individual is given a depression test immediately before therapy, immediately after therapy, and once again 3 months after therapy. The data are to be examined with a repeated-measures ANOVA.

Questions:

1) What does significantly different mean for this scenario?

2) What is the null hypothesis?

3) What is the alternative hypothesis?

4) What is our test statistic?

a. Which variance is affected when the sample means get farther apart? How?

b. Which variance is affected when scores within a group get farther apart from one another? How?

c. What is our expected test-value under the assumed null?

d. Is it a 1-tailed or 2-tailed test?

5) Data:

Before Therapy	After Therapy	3 Months Later	Total
n1=8	n2=8	n3=8	N = 24
T1=136.3	T2 = 134	T3 = 85.1	G = 355.4
SS1 = 25.54	SS2 = 30.14	SS3 = 17.90	k = 3
ΣX2 =2347.75	ΣX2 = 2274.64	ΣX2 = 923.15	ΣX2 =5545.54
M1 = 17.04	M2 = 16.75	M3 =10.64

6) Calculate SS’s:

a. SSTOTAL =

b. SSWITHIN =

c. SSBETWEEN =

7) Compute dfs:

a. dfTOTAL =

b. dfWITHIN =

c. dfBETWEEN =

8) Calculate MS and df necessary for repeated-measures steps:

a. SSBETWEEN SUBJECTS (OR SSINDIVIDUAL DIFFERENCES) =

b. SSERROR =

c. dfBETWEEN SUBJECTS (OR dfINDIVIDUAL DIFFERENCES) =

d. dfERROR =

9) Calculate MS’s:

a. MSBETWEEN =

b. MSERROR =

10) Calculate F-ratio:

a. F =

11) What is our critical value?

12) What do we conclude?

13) What is the calculated effect size?

14) Compute post-hoc tests:

a. Tukey HSD

b. Scheffe

i. Immediately Before vs. Immediately After

Source	SS	df	MS	F
Between
Within
B/S (ID)
Error
Total

ii. Do we reject the null hypothesis?

iii. Immediately Before vs. 3 months later

Source	SS	df	MS	F
Between
Within
B/S (ID)
Error
Total

iv. Do we reject the null hypothesis?

v. Immediately After vs. 3 months later

Source	SS	df	MS	F
Between
Within
B/S
Error
Total

vi. Do we reject the null hypothesis?

Page 4 of 4