Select the item that would be considered a placebo.

A consumer agency wants to determine which of two laundry detergents, A or B, cleans clothes better. Fifty pieces of fabric are subjected to the same kinds of stains (grass, mud, coffee). Then 25 pieces are randomly assigned to be cleaned with detergent A and the remaining 25 pieces are cleaned with detergent B. After being laundered, the pieces of fabric are rated on a scale from 1–10, with 1 being the least clean to 10 being the most clean. The difference in mean ratings (A – B) was determined to be 1.5. Assuming there is no difference in the two detergents, 200 simulated differences in sample mean ratings are displayed in the dotplot.   Using the dotplot and the difference in mean ratings from the samples, is there convincing evidence that the one detergent is better than the other? Yes, because a difference in mean rating of 1.5 or more occurred only 23 out of 200 times, meaning the difference is statistically significant and there is convincing evidence that A is more effective…

by which criteria?

I can't understand why the data is the percentage of surveyed parents.

What are the two types of incorrect decisions?

This is not a test, its practice.

You want to determine how many loaves of Bread are sold per day at Schat’s Bakery. You stand outside for ten different randomly selected days, count the number of loaves, and then average them. You come up with 421 loaves per day. In reality, Schat’s keeps records of how many loaves they sell per day, and in they averaged 395 loaves per day. Describe what the population is in the above example?

Answer it correctly and explain well. I will rate accordingly.

Wegman’s (a food market chain) has developed a new store-brand brownie mix. Before they start selling the mix they want to compare how well people like their brownies to brownies made from a popular national brand mix. In order to see if there was any difference in consumer opinion, Wegman’s asked 124 shoppers to participate in a taste test. Each was given a brownie to try. Subjects were not told which kind of brownie they got—that was determined randomly. 58% of the 62 shoppers who tasted a Wegman’s brownie said liked it well enough to buy the mix, compared to 66% of the others who said they would be willing to buy the national brand. Does this result indicate that consumer interest in the Wegman’s mix is lower than for the national brand?

To determine the amount of sugar in a typical serving of breakfast cereal, a student randomly selected 60 boxes of different types of cereal from the shelves of a large grocery store. The student noticed that the side panels of some of the cereal boxes showed sugar content based on one-cup servings, while others showed sugar content based on three- quarter-cup servings. Many of the cereal boxes with side panels that showed three-quarter-cup servings were ones that appealed to young children, and the student wondered whether there might be some difference in the sugar content of the cereals that showed different-size servings on their side panels. To investigate the question, the data were separated into two groups. One group consisted of 29 cereals that showed one-cup serving sizes; the other group consisted of 31 cereals that showed three-quarter cup serving sizes. The boxplots shown below display sugar content (in grams) per serving of the cereals for each of the two serving sizes.…