Question

14) (20) Does the presence of others affect people's willingness to assume responsibility for the welfare of others? For example, does the presence of other people affect our reaction to potentially dangerous smoke seeping from a wall vent? To answer this question, a researcher measured how long in seconds) it took subjects to ask for help as smoke gradually filled a waiting room. The room was occupied by a subject plus "crowds of either zero, two, or four experimental confederates (confederates are research assistants who pretend they are subjects) who acted as if they were regular subjects but ignored the smoke. Here are some summary data: four confederates two confederates T.39 T=54 zero confederates T= 15 3 S$ - 14 SS-14 SS8 a. (2) What is the independent variable in this experiment, and how many levels does it have? b. (2) What is the dependent variable in this experiment and how is it measured? c. (8) Complete the following summary table. Se has already been computed! SS df MS F Source Between Within Total 294 d. (1) State the critical value for the F-ratio. Set a = .05. e. (1) What is your decision about He: Reject or retain? f (6) Tukey's HSD - 6.14. Use this value to draw specific conclusions about this experiment. Please show any work you do.

Answer 1

a) Independent variable is Confiderates and it is 3 levels i.e. zero confederates , two confederates and frou confederates

b) People willingness

c) From the given data

Given number of samples k=3 Each sample size ni = 3.n,= 3,n; = 3,4 = 3, N = 9 1 15+39 +54 Mean of the sample means x= 7= N- 9 = 12 1 Xi 15 = 5, X 39 = 13,13 54 = 18 3 3 3 i) The variation between the samples 2 2 Treatment sum of square s? = x - x 1-; 1-ܪ i-1 = 3(5– 12)* +3(13-12)* +3(18 - 12) = 258 17) The variation within the samples Error sum of square sº = SS + SS2 + SS3 = 14 +14+8 = 36 111) SS Total=SS Treatment +SS Error = 258 +36 = 294

ANOVA Table				Alpha =	0.05
		Sum of	Mean sum of
Source	df	Squares	Square	F-Ratio	F-crit	P-Value
Between groups	2	258	129	21.5	5.1433	0.0018
Within groups	6	36.00	6
Total	8	294.00

d) Critical value = 5.1433

e) Since F value > F critical value so we reject H0

f) Tukey HSD:

SE = II MS. 6 = 1 V6 Tukey's test statistics M-M 5-13 M vs M2: 912 = = 8 MS 1 Vn Here, 1912/> 6.14 there is significance difference between M, vs M2 M-M 5-18 M vs M3 : 913 = = 13 MS w 3 1 w n 2 = Here, 913 >6.14, there is significance difference between M, vs M, M, -M 13-18 M, vs M3: 923 = 5 MS Vn Here, 1923 146.14, there is no significance difference between M, vs Mz 1