[R] prop.trend.test

[Rui Barradas]

Às 14:23 de 07/09/2023, Thomas Subia via R-help escreveu:
> 
> Colleagues
> 
>   Consider
> smokers  <- c( 83, 90, 129, 70 )
> patients <- c( 86, 93, 136, 82 )
> 
>   prop.trend.test(smokers, patients)
> 
>   Output:
> 
>       Chi-squared Test for Trend inProportions
> 
>   data:  smokers out of patients ,
> 
> using scores: 1 2 3 4
> 
> X-squared = 8.2249, df = 1, p-value = 0.004132
> 
>   # trend test for proportions indicates proportions aretrending.
> 
>   How does one identify the direction of trending?
>   # prop.test indicates that the proportions are unequal but doeslittle to indicate trend direction.
> All the best,
> Thomas Subia
> 
> 
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> 
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Hello,

By visual inspection it seems that there is a decreasing trend.
Note that the sample estimates of prop.test and smokers/patients are equal.


smokers  <- c( 83, 90, 129, 70 )
patients <- c( 86, 93, 136, 82 )

prop.test(smokers, patients)$estimate
#>    prop 1    prop 2    prop 3    prop 4
#> 0.9651163 0.9677419 0.9485294 0.8536585
smokers/patients
#> [1] 0.9651163 0.9677419 0.9485294 0.8536585

plot(smokers/patients, type = "b")



Hope this helps,

Rui Barradas