Sodium ascorbate has been shown to selectively induce apoptosis in cancer cells. (http://www.ncbi.nlm.nih.gov/pubmed/15672419 and http://www.ncbi.nlm.nih.gov/pubmed/16157892). A study of 100 patients with cancers of the stomach, bronchus, colon, ovary or breast were treated with ascorbate and their resulting days of survival were measured. We are interested if the treatment with ascorbate has different mean survival times varying for each type of cancer.
Cameron, E. and Pauling, L. (1978) Supplemental ascorbate in the supportive treatment of cancer: re-evaluation of prolongation of survival times in terminal human cancer. Proceedings of the National Academy of Science USA, 75, 4538Ð4542. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC431183/pdf/pnas00040-0366.pdf
Data found here: http://www.math.umass.edu/~johnpb/s597/cancer.ex
Data was collected by monitoring and following up with the cancer patients in the hospital. The variable, days of survival, is a straightforward variable to measure.
The units of observation are cancer patients receiving ascorbate treatment.
We have the survival time, a discrete numerical variable, for the type of cancer, a categorical variable.
This was an experiment because patients were separated into a control and experimental group. The treatment was given only to the experimental group and all other factors stayed constant.
data <- read.csv("ProjectData.csv", head = TRUE)
summary(data)
## Survival Organ
## Min. : 20 Colon :16
## 1st Qu.: 102 Bronchus :10
## Median : 266 Stomach : 7
## Mean : 559 Breast : 6
## 3rd Qu.: 721 Bronchus: 6
## Max. :3808 Stomach : 5
## (Other) :14
boxplot(data$Survival ~ data$Organ)
The days of survival is variable and widely distributed. There appears to be multiple outliers for a high number of days of survival, perhaps because they didn't die of cancer. There are enough observations for each type of cancer to satisfy conditions.
I plan to run an ANOVA F-test to see if the mean survival days for each type of cancer is equal.
show(data)
## Survival Organ
## 1 124 Stomach
## 2 42 Stomach
## 3 25 Stomach
## 4 45 Stomach
## 5 412 Stomach
## 6 51 Stomach
## 7 1112 Stomach
## 8 46 Stomach
## 9 103 Stomach
## 10 876 Stomach
## 11 146 Stomach
## 12 340 Stomach
## 13 396 Stomach
## 14 81 Bronchus
## 15 461 Bronchus
## 16 20 Bronchus
## 17 450 Bronchus
## 18 246 Bronchus
## 19 166 Bronchus
## 20 63 Bronchus
## 21 64 Bronchus
## 22 155 Bronchus
## 23 859 Bronchus
## 24 151 Bronchus
## 25 166 Bronchus
## 26 37 Bronchus
## 27 223 Bronchus
## 28 138 Bronchus
## 29 72 Bronchus
## 30 245 Bronchus
## 31 248 Colon
## 32 377 Colon
## 33 189 Colon
## 34 1843 Colon
## 35 180 Colon
## 36 537 Colon
## 37 519 Colon
## 38 455 Colon
## 39 406 Colon
## 40 365 Colon
## 41 942 Colon
## 42 776 Colon
## 43 372 Colon
## 44 163 Colon
## 45 101 Colon
## 46 20 Colon
## 47 283 Colon
## 48 1234 Ovary
## 49 89 Ovary
## 50 201 Ovary
## 51 356 Ovary
## 52 2970 Ovary
## 53 456 Ovary
## 54 1235 Breast
## 55 24 Breast
## 56 1581 Breast
## 57 1166 Breast
## 58 40 Breast
## 59 727 Breast
## 60 3808 Breast
## 61 791 Breast
## 62 1804 Breast
## 63 3460 Breast
## 64 719 Breast