Question

QUESTION 16

Analyse the data below related to days survival following surgery from either stomach or lung cancer. What is the result of the Kolmogorov–Smirnov test for the patients who survived stomach cancer?

ID	Group	Days
1	Stomach	223
2	Stomach	224
3	Stomach	151
4	Stomach	300
5	Stomach	246
6	Stomach	166
7	Stomach	100
8	Stomach	111
9	Stomach	155
10	Stomach	247
11	Stomach	151
12	Stomach	166
13	Stomach	99
14	Bronchus	223
15	Bronchus	138
16	Bronchus	72
17	Bronchus	245
18	Bronchus	124
19	Bronchus	368
20	Bronchus	112
21	Bronchus	555
22	Bronchus	412
23	Bronchus	111
24	Bronchus	1112
25	Bronchus	479
26	Bronchus	103
27	Bronchus	876
28	Bronchus	146
29	Bronchus	340
30	Bronchus	396

a.		D(13) = .203, p = .146
b.		D(17) = .175, p = .173
c.		D(13) = .930, p = .344
d.		D(17) = .821, p = .004

QUESTION 17

Run an independent t-test on the data in Q16. A Levene’s test result of p = .006 was obtained. What can we infer from this number?

	a.	The stomach and lung cancer variance is heterogeneous.
	b.	The stomach and lung cancer variance is homogenous.
	c.	The distributions look fairly similar.
	d.	The result is inconclusive.

QUESTION 18

What is the correct result for the independent t-test you calculated in Q17?

	a.	t(17.95) = –2.24, p = .038
	b.	t(28) = –1.98, p = .058
	c.	t(17.95) = –2.24, p = .006
	d.	t(28) = –1.98, p = .006

  

QUESTION 19

Assume that for the research into stomach and lung cancer the significance value is set at p < .05 and an independent t-test yielded a significance value of p = .06. What should you do?

	a.	Accept the null hypothesis and state that there is no difference in the duration of the survival between the two types of cancer.
	b.	Reject the null hypothesis and state that there is a difference in the duration of the survival between the two types of cancers.
	c.	Accept the null hypothesis and state that there is no difference in the duration of the survival between the two types of cancer, but that it is worth further investigation.
	d.	The results are inconclusive.

QUESTION 20

What is the effect size for the cancer survival data?

	a.	0.5
	b.	0.7
	c.	0.1
	d.	0.3

Answer 1

16.> data1=read.csv(file.choose(),header=T)
> attach(data1)
> names(data1)
[1] "ID" "Group" "Days"
> Days[Group=="Stomach"]
[1] 223 224 151 300 246 166 100 111 155 247 151 166 99

> mean(Days[Group=="Stomach"])
[1] 179.9231

> sd(Days[Group=="Stomach"])
[1] 62.88278
> ks.test(Days[Group=="Stomach"],pnorm,179.9231,62.88278)

One-sample Kolmogorov-Smirnov test

data: Days[Group == "Stomach"]
D = 0.203, p-value = 0.6576 Option(a)
alternative hypothesis: two-sided

Warning message:
In ks.test(Days[Group == "Stomach"], pnorm, 179.9231, 62.88278) :
ties should not be present for the Kolmogorov-Smirnov test

17. Levene's test with p=0.006 indicates : Option (a) The stomach and lung cancer variance is heterogeneous, since p-value < 0.05 which means rejection of null hypothesis of equal variance.

18.> t.test(Days~Group,paired=F)

Welch Two Sample t-test

data: Days by Group
t = 2.2409, df = 17.948, p-value = 0.03792 Option(a)
alternative hypothesis: true difference in means is not equal to 0
95 percent confidence interval:
10.08412 313.83443
sample estimates:
mean in group Bronchus mean in group Stomach
341.8824 179.9231

19. p-values = 0.06 > 0.05 indicates : Option (a) Accept the null hypothesis and state that there is no difference in the duration of the survival between the two types of cancer.