Calculate the $90\%$ confidence interval for the difference $($mu$1-$mu$2)$ of two population means given the following sampling results. Population $1$: sample size $=13,$ sample mean $=21\mathrm{.}18,$ sample standard deviation $=1\mathrm{.}72.$ Population $2$ : sample size $=17,$ sample mean $=12\mathrm{.}54,$ sample standard deviation $=3\mathrm{.}00.$

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