A Local Consumer Reporter Wants to Compare the Average Costs

A local consumer reporter wants to compare the average costs of grocery items purchased at three different supermarkets, A, B, and C. Prices (in dollars) were recorded for a sample of 60 randomly selected grocery items at each of the three supermarkets. In order to reduce item-to-item variation, the prices were recorded for each item on the same day at each supermarket.

$\begin{array} { l l c c c } \hline & { \text { Item } } & \mathrm { A } & \mathrm { B } & \mathrm { C } \\\hline 1 ) & \text { paper towels } & 1.21 & 1.41 & 1.36 \\2 ) & \text { cereal } & 2.84 & 3.29 & 3.04 \\\text { 3) } & \text { floor cleaner } & 5.97 & 5.85 & 6.86 \\\vert &\vert&\vert&\vert& \vert \\59 ) & \text { shaving cream } & 1.04 & 0.94 & 1.00 \\\text { 60) } & \text { canned green beans } & 0.53 & 0.68 & 0.45 \\\hline\end{array}$

Identify the treatments for this experiment.

A) the three supermarkets
B) the 60 grocery items
C) the day on which the data were collected
D) the $60 \times 3 = 180$ prices