Plot by groups

[anne jagdberg]

Hello I have a very basic problem, unfortunately the forum posts could not help me. so thank you in advance if anyone can help me.

I run a regression as follows:


foreach x of numlist 1 2 3 4 {
reg sport time if group==`x'
}

sport is the duration of sports per week in hours
group is a categorial variable because i want to see if people of different groups differ

so i want to see the development of hours of sports across time in different groups (i do not want to incude interaction effects but use the if command, i hope it is possible like that)

I would like to have a graph of this:
y-achsis: hours of sports
x-achsis: time
and then i would like to have for each of the groups one line in the graph.

does this work with twoway connected?
sorry i dont get it :-(

maybe one can help?
thank you so much!!!

best

[Ken Chui]

Do you mean something like this?

sysuse nlsw88, clear

twoway (lfit wage age if race == 1) ///
       (lfit wage age if race == 2) ///
       (lfit wage age if race == 3), ///
       legend(label(1 White) label(2 Black) label(3 Other) cols(3))

Using connected to plot the regression line would first require saving the predicted values:

foreach x in 1 2 3{
    quietly reg wage age if race == `x'
    predict yhat`x'
}

twoway (connected yhat1 age if race == 1) ///
       (connected yhat2 age if race == 2) ///
       (connected yhat3 age if race == 3), ///
       legend(label(1 White) label(2 Black) label(3 Other) cols(3))

[anne jagdberg]

YES!
Exactly what i meant. thats perfect. you are the heroe of my day!!!!
i very much appreciate your answer.

perfect