c. A researcher suspects that the effectiveness of the different strategies for lowering the amount of salt intake is affected by the education level of the subjects. There- fore, she used a 6 x 4 factorial design with three replicates in each cell to examine her conjecture. The data is summarized in the following table.

Each day, the average Canadian consumes excessive amounts of sodium-an average of 3,100 milligrams-more than double the adequate intake. There is no recommend- ed daily intake (RDI) for sodium... but there are adequate daily intake and tolerable upper intake levels. 3100 is more than double the 1200 to 1500 AI. The adequate daily intake for a healthy adult is 1,200 mg to 1,500 mg of sodium according to Health Canada and the U.S. National Academy of Sciences (Institute of Medicine) and a tolerable upper intake level is 2,300 mg. Statistics Canada estimates the average Canadian consumes more than 3,100 mg of sodium daily, making the goal of between 1,200 mg and 2,300 mg a significant reduction.

(i) Identify the experimental design. (ii) Test at the 5% significance level whether there are differences among the means of each of the six strategies. (iii) Do the data provide sufficient evidence to indicate an interaction between strategy and education level? Test using a = 0.05. (iv) What are the practical implications of the test results on the previous question? (v) Test at 10% significance level to determine if differences exist among the means of the education levels of the subjects. (vi) Find a 95% confidence interval for the difference in mean between high school and postgraduate education levels if the subjects were using Strategy 6.

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Strategies Less Than High School Education level University/ High School. College Postgraduate Strategy 1 2.5 2.7 Strategy 2 Strategy 3 Strategy 4 Strategy 5 Strategy 6 1 2 3 3 3 3 38 922832 323 3.2 2.6 2.3 2.3 2.9 3.1 3.0 2.6 3.0 2.6 2.9 3.0 222222222222222 222 27 2.9 2.8 2.1 2.9 2.5 2.7 2.8 2.5 2.7 2.4 2.3 2.7 2.4 2.9 2.6 2.4 2.3 2.4 2.9 2.5 2.3 2.7 2.4 2.5 2.2 2.4 2.3 27 2.6 2.5 2.2 2.3 2.1 2.0 2.0 222222222222222222 2.4 2.3 2.5 2.3 2.4 2.5 2.1 2.5 2.1 2.0 2.4 1.9 2.5 1.9 1.7 1.4.