307 Diamonds Were Sampled and Randomly Sorted into Three Groups $\text {One-Way AOV for CARAT by CERT}$

307 diamonds were sampled and randomly sorted into three groups of diamonds. These diamonds were randomly assigned to one of the three organizations, or groups (HRD, GIA, or IGI), that certify the appraisal of diamonds. A study was conducted to determine if the average size of diamonds reported by these three certification groups differ. A completely randomized design was used and the resulting ANOVA table is shown below. $\text {One-Way AOV for CARAT by CERT}$
$\begin{array}{lccccc}\text { Source } & \text { DF } & \text { SS } & \text { MS } & \text { F } & \text { P } \\\hline \text { CERT } & 2 & 8.3265 & 4.16326 & 83.21 & 0.0000 \\\text { Error } & 305 & 15.2604 & 0.05003 & & \\\text { Total } & 307 & 23.5869 & & &\end{array}$

Specify the null hypothesis for a test to compare the mean size of a diamond for the three certification groups (HRD, GIA, and IGI).
A) $\mathrm { H } _ { 0 } : \mu = 0$ , where $\mu =$ mean carat weight.
B) $\mathrm { H } _ { 0 } : \mu _ { \mathrm { HRD } } = \mu _ { \mathrm { GIA } } = \mu _ { \mathrm { IGI } }$ , where $\mu _ { \mathrm { j } } =$ mean carat weight for certification group i
C) $\mathrm { H } _ { 0 } : \mu _ { \mathrm { HRD } } = \mu _ { \mathrm { GIA } } = \mu _ { \mathrm { IGI } } = 0$ , where $\mu _ { \mathrm { j } } =$ mean carat weight for certification group i
D) At least two of the population mean carat weights differ for the three certification groups.