At 09:34 AM 5/4/2008, Armelini, Guillermo wrote:
Hi everybody,
Does anyone who knows how can i store the T value of the T Test in a
local macro?
Two-sample t test with equal variances
------------------------------------------------------------------------------
Group | Obs Mean Std. Err. Std. Dev. [95%
Conf. Interval]
---------+--------------------------------------------------------------------
1
| 77 3.402597 .0872214 .7653644 3.228881 3.576314
2
| 13 3.615385 .2129904 .7679476 3.151318 4.079451
---------+--------------------------------------------------------------------
combined | 90 3.433333 .0806497 .76511 3.273084 3.593583
---------+--------------------------------------------------------------------
diff
| -.2127872 .2296004 -.6690697 .2434953
------------------------------------------------------------------------------
diff = mean(1) - mean(2) t
= -0.9268
Ho: diff = 0 degrees of freedom = 88
Ha: diff < 0 Ha: diff != 0 Ha: diff > 0
Pr(T < t) = 0.1783 Pr(|T| > |t|) = 0.3566 Pr(T >
t) = 0.8217
I would like to store t ( in this case -0.9268) and the p-value (in
this case 0.1783)
The information you want is stored in r, e.g.
. webuse auto
(1978 Automobile Data)
. ttest price, by(foreign)
Two-sample t test with equal variances
------------------------------------------------------------------------------
Group | Obs Mean Std. Err. Std. Dev. [95% Conf. Interval]
---------+--------------------------------------------------------------------
Domestic | 52 6072.423 429.4911 3097.104 5210.184 6934.662
Foreign | 22 6384.682 558.9942 2621.915 5222.19 7547.174
---------+--------------------------------------------------------------------
combined | 74 6165.257 342.8719 2949.496 5481.914 6848.6
---------+--------------------------------------------------------------------
diff | -312.2587 754.4488 -1816.225 1191.708
------------------------------------------------------------------------------
diff = mean(Domestic) - mean(Foreign) t = -0.4139
Ho: diff = 0 degrees of freedom = 72
Ha: diff < 0 Ha: diff != 0 Ha: diff > 0
Pr(T < t) = 0.3401 Pr(|T| > |t|) = 0.6802 Pr(T > t) = 0.6599
. return list
scalars:
r(sd) = 2949.49588476892
r(sd_2) = 2621.915083190759
r(sd_1) = 3097.104279086425
r(se) = 754.4488373823767
r(p_u) = .6599074558726947
r(p_l) = .3400925441273052
r(p) = .6801850882546103
r(t) = -.4138898832983144
r(df_t) = 72
r(mu_2) = 6384.681818181818
r(N_2) = 22
r(mu_1) = 6072.423076923077
r(N_1) = 52
-------------------------------------------
Richard Williams, Notre Dame Dept of Sociology
OFFICE: (574)631-6668, (574)631-6463
HOME: (574)289-5227
EMAIL: [email protected]
WWW: http://www.nd.edu/~rwilliam
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