Question

please show all steps and calculations

Scenario 2. The endorphins released by the brain act as natural painkillers. A researcher monitored the endorphin activity and pain thresholds of pregnant rats during the days before they gave birth. The data showed an increase in pain threshold as the pregnancy progressed. The change was gradual until 1 or 2 days before birth, at which point there was an abrupt ncrease in the pain threshold. Apparently a natural painkilling mechanism was preparing the animals for the stress of giving birt obtained during the study. Do these data indicate a significant change in pain threshold? h. The foll owing data represent pain-threshold scores Days before giving birth Rat7 BI 38 DI 40 A| 39 | 40 49 52 M.- 451 55 м,-44 Mc 50 Mp 46 м.- 40 Ms M M GM45 39 46 42 50 46 56 41 El 34 52 39 40 SSs 90 46 55 SSTotal 1050 52 54 Source Between-conditions Within-conditions df MS Subjects Error Total Step 1. Describe the populations, distribution, and assumptions. For this step, please only test the assumption on homogenety of variances 7 days s2- 5 days s2- 3 days s2- I day s2- Step 2. State the null and research hypotheses. Assignment # 1 5: Within-Subjects ANOVA Step 3. Determine the characteristcs of the comparison distribution. Step 4. Determine the critical values. Step 5. Calculate the test statistic Step 6. Make a decision and report your findings in APA format. Calculate the effect size for this ANOVA using the following equation: Effect size in R2: R2 SSbetween Please run Tukey's HSD post-hoc tests to compare each condition. Which conditions are SStotal-SSsubjects different from one another?

Answer 1

SOLUTION

null hypothesis:Ho: there is no change in pain threshold in groups of different days

alternate hypothesis:Ha: there is signficant change in pain threshold in groups of different days

blocks treatments nj Total-Vi Average YsEY/nj 7 day 5 day 195 200 230 275 39 38 34 39.0000 40.0000 46.0000 55.0000 49 1 day 52 176 44.0000 7926 184 46.0000 8616 160 40.0000 6630 Average-x-2</ nF 45.0000 50.0000 Grandmean 45.0000 Total-EX 8226 10152 41550.00 Total observation number of treatments number of Blocks treatments degree of freedom dft k-1- Blocks degree of freedom dfbbm-1- within(Error) degree of freedom (k-1)*(m-1) Total degree of freedom Treatments 12 dfTotal IN-1) 19 n,"( Grand,mean)" 180.000 125.000 5.000 500.000 810.000 7 day 39.0000 40.0000 46.0000 55.0000 SSTr 3 da 1 day total Blocks n(X-Grandmean) 45 0.000 4.000 100.000 4.000 100.000 208.000 4 total SSB sum of square between treatments SSTr 810.00 208.00 1050.00 32.000 Zn'(Yi-Grand,mean)"- n(X-Grandmen) sum of square between blocks -SSB total sum of square sum of square within(Error) SSE SST SST-SSTr-SSB- Summary table Source of variation Between Treatments Between Blocks within(Error) total MS 270.000 52.000 2.667 5.953 810.000 208.000 32.000 1050.000 101.25 12 19

as test statsitic is greater then critical value at 0.01 level ; therefore we reject null hypothesis

we have sufficient evidence to conclude that  there is signficant change in pain threshold in groups of different days