Question

10) Correctional services were interested in further evaluating a cognitive-behavioural based intervention. The same group of researchers randomly assigned 15 offenders into a low intensity, medium intensity, or high intensity intervention program. The researchers then gathered data on the number of violent incidents perpetrated by offenders over the five years after their release. They were interested in whether the intensity of the intervention program had any effect on the outcome.

Low : 9 8 6 8 7

Medium: 8 7 5 6 8

High: 5 6 7 4 3

a) What is the appropriate model of the population(s)?

b) What are the appropriate hypotheses for this analysis?

c) What is/are the critical value(s) for this test using an alpha of 0.05?

d) What is the observed value of the appropriate test statistic?

e) What is your decision regarding the stated hypotheses?

Please bold answers and show steps.

Answer 1

For the given data using Anova single factor in Excel we get output as

Anova: Single Factor
SUMMARY
Groups	Count	Sum	Average	Variance
low	5	38	7.6	1.3
medium	5	34	6.8	1.7
high	5	25	5	2.5
ANOVA
Source of Variation	SS	df	MS	F	P-value	F crit
Between Groups	17.73333	2	8.866667	4.836364	0.028814	3.885294
Within Groups	22	12	1.833333
Total	39.73333	14

So from the above output