USE R LAB TO SOLVE THIS test the hypothesis that all four types of plants reach the same maximum height, scientists selected

six greenhouses. In each greenhouse, one of each of four types of plants was planted. The plant heights

$($in centimeters$)$ are recorded as following:

$($a$)$ What type of experimental design is this? $-$ randomized complete block design

$($b$)$ Test the hypothesis that all four types of plants reach the same maximum height.

Use greenhouse as random factors, and plant type $($variety$)$ as fixed factor