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      name:  <unnamed>
       log:  C:\Users\LabProf01\Documents\Aula_2209.log
  log type:  text
 opened on:  22 Sep 2022, 15:45:01

. twoway (scatter bp agegrp if when==1)

.  twoway (scatter bp agegrp if when==1)  twoway (scatter bp agegrp if when==2)
twoway is not a twoway plot type
r(198);

.  twoway (scatter bp agegrp if when==1)   (scatter bp agegrp if when==2)

.  twoway (line bp agegrp if when==1)

. tab when, sum(bp)

            |      Summary of Blood pressure
     Status |        Mean   Std. Dev.       Freq.
------------+------------------------------------
     Before |      156.45   11.389845         120
      After |   151.35833   14.177622         120
------------+------------------------------------
      Total |   153.90417   13.083702         240

. display  (156.45-151.3583)/( 11.38985 ^2/120+14.17762^2/120)^0.5
3.0670035

. * z>1.96 => rejeitar H0

. ztest bp, by(when) sd1(11.389845) sd2( 14.177622)

Two-sample z test
------------------------------------------------------------------------------
   Group |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
  Before |     120      156.45    1.039746    11.38984    154.4121    158.4879
   After |     120    151.3583    1.294234    14.17762    148.8217     153.895
---------+--------------------------------------------------------------------
    diff |            5.091667    1.660154                1.837824     8.34551
------------------------------------------------------------------------------
    diff = mean(Before) - mean(After)                             z =   3.0670
Ho: diff = 0

    Ha: diff < 0                 Ha: diff != 0                 Ha: diff > 0
 Pr(Z < z) = 0.9989         Pr(|Z| > |z|) = 0.0022          Pr(Z > z) = 0.0011

. xtset patient when
       panel variable:  patient (strongly balanced)
        time variable:  when, 1 to 2
                delta:  1 unit

. by patient: gen diff=bp[2]-bp[1]

. replace diff=. if when==1
(120 real changes made, 120 to missing)

. sum diff

    Variable |        Obs        Mean    Std. Dev.       Min        Max
-------------+---------------------------------------------------------
        diff |        120   -5.091667     16.7136        -45         41

. ztest diff==0, sd( 16.7136  )

One-sample z test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
    diff |     120   -5.091667    1.525736     16.7136   -8.082054   -2.101279
------------------------------------------------------------------------------
    mean = mean(diff)                                             z =  -3.3372
Ho: mean = 0                                     

    Ha: mean < 0                 Ha: mean != 0                 Ha: mean > 0
 Pr(Z < z) = 0.0004         Pr(|Z| > |z|) = 0.0008          Pr(Z > z) = 0.9996

. display (-5.091667 -0)/ (16.7136 ^2/120)^0.5
-3.3371875

. tab agegrp when, sum(bp)

       Means, Standard Deviations and Frequencies of Blood pressure

           |       Status
 Age Group |    Before      After |     Total
-----------+----------------------+----------
     30-45 |   151.675    144.325 |       148
           | 9.2580872  11.893518 | 11.217076
           |        40         40 |        80
-----------+----------------------+----------
     46-59 |     155.1    150.775 |  152.9375
           | 11.459628  14.502851 | 13.168185
           |        40         40 |        80
-----------+----------------------+----------
       60+ |   162.575    158.975 |   160.775
           | 10.727122  12.286093 | 11.602024
           |        40         40 |        80
-----------+----------------------+----------
     Total |    156.45  151.35833 | 153.90417
           | 11.389845  14.177622 | 13.083702
           |       120        120 |       240

. tab agegrp, sum(diff)

            |           Summary of diff
  Age Group |        Mean   Std. Dev.       Freq.
------------+------------------------------------
      30-45 |       -7.35   15.938262          40
      46-59 |      -4.325   19.751517          40
        60+ |        -3.6   14.145399          40
------------+------------------------------------
      Total |  -5.0916667   16.713601         120

. ztest diff==0 if agegrp==3, sd(14.145399 )

One-sample z test
------------------------------------------------------------------------------
Variable |     Obs        Mean    Std. Err.   Std. Dev.   [95% Conf. Interval]
---------+--------------------------------------------------------------------
    diff |      40        -3.6    2.236584     14.1454   -7.983624     .783624
------------------------------------------------------------------------------
    mean = mean(diff)                                             z =  -1.6096
Ho: mean = 0                                     

    Ha: mean < 0                 Ha: mean != 0                 Ha: mean > 0
 Pr(Z < z) = 0.0537         Pr(|Z| > |z|) = 0.1075          Pr(Z > z) = 0.9463

. * pvalue>0.05 => nao rejeita H0

. ttest diff==0 if agegrp==3, sd(14.145399 )
option sd() not allowed
r(198);

. display (-3.6-0)/(14.1454 ^2/40)^0.5
-1.6095974

. * 1.60<2.023 => nao rejeita H0, utilizando-se um teste bicaudal com amostra peq
> uena

. *tabela t-student

. log close
      name:  <unnamed>
       log:  C:\Users\LabProf01\Documents\Aula_2209.log
  log type:  text
 closed on:  22 Sep 2022, 16:50:20
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