* Stata syntax for KLMED8008, Day1.
use gtube, replace 
list in 1/20 // slide no. 14

* 'long' format is needed to make a plot
gen id = _n // this creates an id variable
reshape long t, i(id) j(time) // converts to long format
save gtube_l, replace // save this file for possible later use

twoway scatter t time, by(grp) jitter(10) /// slide no. 15. Kjør tre linjer i ett 
xtitle(Time of evaluation) ///
ytitle(Nausea grade)


* Back to the 'wide' format again
use gtube, replace // 
egen m = rowmean (t*) // t* svarer til (t1 t2 t3 t4 t5 t6)
egen md = rowmedian (t*)
egen mx = rowmax (t*)
egen m4 = anymatch (t*), values(4)
egen m34 = anymatch (t*), values(3 4)

list in 1/20 // slide 16

* Various tests
ttest m, by(grp)  // slide 17
ttest md, by(grp)
ttest mx, by(grp)
tabulate grp m4, chi
tabulate grp m34, chi // slide 17

* venous oxygen example
use x67, clear
list // slide 30
summ x6 x7 // needed for the reference lines
graph twoway (scatter x7 x6), yline(30.75) xline(35.1) // slide 31

cor x6 x7, cov mean // upper part, slide 32          
pwcorr x6 x7, star (0.05) sig // lower part, slide 32

gen D = x7 - x6 // slide 35
list // slide 37
summ D, detail // slide 38
ttest D ==0 // slide 39

* Now using the "shuffeled" x7
use x67s, clear
gen D = x7s - x6 // slide 40
graph twoway (scatter x7s x6), yline(30.75) xline(35.1) // slide 42

cor x6 x7s, cov mean // slide 44
pwcorr x6 x7s, star (0.05) sig  // slide 44

summ D, detail // slide 45
ttest D ==0 // slide 46