Chapter 5: ANOVA 1. A using the formulas for the One Way Repeated Measures ANOVA below, Calculate the F statistic for the data. N 1 2 3 4 5 6 Group1 8 7 8 6 9 7 Step 1: Calculate sum of all scores squared ∑X2 Answer: Total Squares= 660. Step 2: Calculate the correction factor ∑(X) 2 / N G= Grand total of all of the scores added together N= number of scores in the table Answer: Correction Factor =10816/18 =600.8889 Step 3: Calculate the Model Sum of Squares SSModel ∑C2 / Ncorrection - factor DoFModel= k-1 Where: C= Total score per condition (i.e. column sum) N= Amount of participants in the experiment (6) k= Amount of conditions (in this case, groups) DoFModel= Model Degrees of Freedom Answer: C - Group 1= 45; C Group 2= 36; C Group 3= 23 SSModel= ((2025+1296+529) / 6)- 600.889 = ((2025+1296+529) / 6)- 600.889 Group2 6 7 5 5 8 5 Goup3 5 3 3 5 4 3 = ((3850) / 6)- 600.889 = 641.6667-600.889 = 40.77778 DoFModel= 3-1=2 Step 4: Calculate the Error Sum of Squares SSError ∑X2 - ∑ 𝑐 2 / N - ∑ 𝑝2 / K + correction - Factor DoFError= (k-1)(N-1) Where: P= total score per participant (i.e. row sum) N= Number of participants in the experiment k= number of conditions in the experiment DoFError= Error Degrees of Freedom Answer: P- Participant (row) 1= 19; Participant (row) 2=17; Participant (row) 3=16 Participant (row) 4=16; Participant (row) 5=21; Participant (row) 6=15 SSerror = 660- 641.6667-((361+289+256+256+441+225)/3)+600.889 SSerror = 660- 641.6667-(1828/3)+600.889 SSerror = 660- 641.6667-609.3333+600.889 SSerror = 9.889 DoFError= 2x5=10 Step 5: Calculate Mean Square Model & Mean Square Error MSModel SSModel lDoFmod el MSError SSErrorDoFError Answer: MS model= 40.77778/2 = 20.38889 MS error= 9.889/10 = 0.9889 Step 6: Calculate the F Ratio F MSModel / MSError Answer: F=20.38889 Chapter6: Chi-Square Let X be the number of defects in printed circuit boards. A random sample of n = 60 Printed circuit boards are taken and the number of defects recorded. The results were as follows: Number Of Defects 0 1 2 3 Observed Frequency 32 15 9 4 Does the assumption of a Poisson distribution seem appropriate as a model for these data? The null hypothesis is HO : X ------- Poisson The alternative hypothesis is H1 : X ------------ does not follow a Poisson distribution. Calculating Poisson distribution Probabilities: μ = (32 × 0) + (15 × 1) + (9 × 2) + (4 × 3)/60 = 0.75 p0 = P(X = 0) = 𝑒 −0.75(0.750 ) / 0! = 0.472 E= 0.472*60= 28.32 p1 = P(X = 1) =𝑒 −0.75(0.751 ) / 1! =0.354 E1 = 0.354 × 60 = 21.24 p2 = P(X = 2) =𝑒 −0.75(0.752 ) / 2! = 0.133 E2 = 0.133 × 60 = 7.98 p3 = P(X _ 3) = 1 − (p0 + p1 + p2) = 0.041 E3 = 0.041 × 60 = 2.46 Calculating 𝑥 2 Number of Defects 0 1 2 or more Observed Frequency 32 15 9 Expected Frequency 28.32 21.24 10.44 𝑥 2 = ∑(𝑂 − 𝐸)2 /𝐸 (32 − 28.32)2/28.32 +(15 − 21.24)2/21.24 +(13 − 10.44)2/10.44 = 2.94 Df= K – P – 1 df= 3-1-1=1 P-value from the table = 0.1 0.1>0.05 Decision: Reject H0