(Exam 1 Summer 2020) Use the preamble below to answer the questions that follow An experiment to gain a better understanding of the role of various substances in melting ice was run in 2004 by Edinson Cavani, a researcher, in a certain lab in Memphis, TN. For each observation, a 10 ml block of ice was placed into water containing a given concentration of sugar, or salt, or a sugar and salt mix. The melting time for the ice block was measured in seconds and then converted to minutes. The three factors of interest were shape of ice block (lozenge, cylinder, and cube), solute (sugar, salt, and equal mix of sugar and salt), and concentration (5%, 10% 15%, 20%). (a) What is the response(outcome) variable for this study?
(b) How many unique treatment combinations are there? Suppose there were two replicates per treatment combination, what is the total number of trials?
i. Number of unique treatment combinations
ii. Total number of trials
(c) Would you say the experiment was run as a completely randomized design(CRD) or as a ran- domized complete block design(RCBD)? Support your answer with reason.
(d) If the experiment had to be run in two labs with a different technician in each lab, which design type would be more appropriate: a CRD or a RCBD? Briefly explain.