Develop manufacture hierarchical model ([Stan](https://github.com/hyunjimoon/defense-reliability/blob/master/R/2_Theta_bar_Y/spline/models/layer3_nc.stan),[R](https://github.com/hyunjimoon/defense-reliability/blob/8ee067949422c2dabb7475ed25bef7fc651d6882/R/2_Theta_bar_Y/spline/forklift.R#L23) such as below: - different s_Y to all manufactures - using more robust distribution (normal to cauchy) compare elpd, mse from the original and log it in google docs.
