Stat Computing > Stata > Textbook Examples > Intro Practice Statistics, by Moore and McCabe

Stata Textbook Examples
Introduction to the Practice of Statistics by Moore and McCabe
Chapter 6: Introduction to Inference

Examples 6.2-6.5, just calculator examples. Below we show that Stata can be used as a calculator using 6.2-6.4 as examples

Example 6.2

display (190.5 + 189 + 195.5 + 187) / 4
190.5

display 190.5 - 1.645*(3/sqrt(4))
188.0325

display 190.5 + 1.645*(3/sqrt(4))
192.9675

Example 6.3

display 190.5 - 1.645*(3/sqrt(1))
185.565

display 190.5 + 1.645*(3/sqrt(1))
195.435

Example 6.4

display 190.5 - 2.576*(3/sqrt(1))
182.772

display 190.5 + 2.576*(3/sqrt(1))
198.228

Bootstrap example, bottom of page 445

clear
input weight 
190.5
189
195.5
187
end

Below we take 100 samples. You can control the number of samples with the reps option.

* Stata 8 code.
bs "summarize weight" r(mean), reps(100)

* Stata 9 code and output.
bootstrap r(mean), reps(100) nodots: summarize weight

Bootstrap results                               Number of obs      =         4
                                                Replications       =       100

      command:  summarize weight
        _bs_1:  r(mean)

------------------------------------------------------------------------------
             |   Observed   Bootstrap                         Normal-based
             |      Coef.   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
       _bs_1 |      190.5   1.742532   109.32   0.000     187.0847    193.9153
------------------------------------------------------------------------------

estat bootstrap, all

Bootstrap results                               Number of obs      =         4
                                                Replications       =       100

      command:  summarize weight
        _bs_1:  r(mean)

------------------------------------------------------------------------------
             |    Observed               Bootstrap
             |       Coef.       Bias    Std. Err.  [95% Conf. Interval]
-------------+----------------------------------------------------------------
       _bs_1 |       190.5    -.08125   1.7425323    187.0847   193.9153   (N)
             |                                          187.5     194.25   (P)
             |                                        187.875     194.25  (BC)
------------------------------------------------------------------------------
(N)    normal confidence interval
(P)    percentile confidence interval
(BC)   bias-corrected confidence interval

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