In a local community there are three grocery chain stores. The three have been carrying out a spirited advertising campaign in which each claims to have the lowest prices. A local news station recently sent a reporter to the three stores to check prices on several items. She found that for certain items each store had the lowest price. This survey didn't really answer the question for consumers. Thus, the station set up a test in which 20 shoppers were given different lists of grocery items and were sent to each of the three chain stores. The sales receipts from each of the three stores are recorded in the data file Groceries. Based on a significance level of 0.05 and these sample data, test to determine whether blocking was necessary in this example. Use a test-statistic approach.
A) Since 952.6155 1.8673 do not reject H0 and conclude that there is an indication that blocking was not effective.
B) Since 952.6155 1.8673 reject H0 and conclude that there is an indication that blocking was effective.
C) Since 102.2912 1.8673 do not reject H0 and conclude that there is an indication that blocking was not effective.
D) Since 102.2912 1.8673 reject H0 and conclude that there is an indication that blocking was effective.

Question

In a local community there are three grocery chain stores. The three have been carrying out a spirited advertising campaign in which each claims to have the lowest prices. A local news station recently sent a reporter to the three stores to check prices on several items. She found that for certain items each store had the lowest price. This survey didn't really answer the question for consumers. Thus, the station set up a test in which 20 shoppers were given different lists of grocery items and were sent to each of the three chain stores. The sales receipts from each of the three stores are recorded in the data file Groceries. Based on a significance level of 0.05 and these sample data, test to determine whether blocking was necessary in this example. Use a test-statistic approach.
A) Since 952.6155 > 1.8673 do not reject H0 and conclude that there is an indication that blocking was not effective.
B) Since 952.6155 > 1.8673 reject H0 and conclude that there is an indication that blocking was effective.
C) Since 102.2912 > 1.8673 do not reject H0 and conclude that there is an indication that blocking was not effective.
D) Since 102.2912 > 1.8673 reject H0 and conclude that there is an indication that blocking was effective.

Quizplus · Accepted Answer

Blocking is a technique used in experimental design to reduce the effects of confounding variables, and it is considered effective if it significantly affects the outcome. In this context, rejecting the null hypothesis (H0) indicates that there is a statistically significant difference in the total costs among the stores, suggesting that the blocking (i.e., using different lists of grocery items for different shoppers) was effective in revealing differences among the stores. The test statistic value (952.6155) being greater than the critical value (1.8673) leads to the rejection of H0, supporting the effectiveness of blocking.

In a Local Community There Are Three Grocery Chain Stores