Is the model $$ y = \gamma_0 + \gamma_1 + \sqrt x + \varepsilon $$ linear in parameters? ( $\varepsilon$ is the error term.)


marked as duplicate by gung, kjetil b halvorsen, Harvey Motulsky, Nick Cox, StasK Jan 26 '15 at 20:12

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    $\begingroup$ Is this a homework problem? I'm guessing it is. If so, here's a hint. The gamma's are the parameters. $\endgroup$ – StatsStudent Jan 26 '15 at 17:39
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    $\begingroup$ I think this may be written incorrectly. I believe it should be $\gamma_1\sqrt{x}$, correct? $\endgroup$ – StatsStudent Jan 26 '15 at 17:42
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    $\begingroup$ @StatsStudent: Homework or not, we need to be told what the free parameters are, especially as the model is unidentifiable as it stands. $\endgroup$ – Scortchi Jan 26 '15 at 17:42
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    $\begingroup$ @StatsStudent, that is a reasonable guess. The model as stated is clearly unidentifiable. However, I just added $\TeX$, I didn't add the "$+$". $\endgroup$ – gung Jan 26 '15 at 17:43
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    $\begingroup$ In any case, the concept of "linear in the parameters" is explained here, here, here, here, here, & here. $\endgroup$ – Scortchi Jan 26 '15 at 17:58