Choosing the Appropriate Inference Procedure Answers

From previous experience, the owner of an apple orchard knows that the mean weight of gala apples is 140 grams. This year there has been more precipitation than usual and the owner believes the weights of the apples are heavier than usual. The owner takes a random sample of 30 apples and records their weights.What type of sampling is described in this study?

The owner of a computer company wants to estimate the difference in the proportion of defective computer chips produced by plant A and produced by plant B. A random sample of 100 chips is collected from each plant and the difference in the proportion of defective chips is calculated.What is the appropriate inference procedure?

The owner of an apple orchard wants to estimate the mean weight of the apples in the orchard. She takes a random sample of 30 apples, records their weights, and calculates the mean weight of the sample.What is the appropriate inference procedure?

A biologist claims that warmer temperatures affect the growth of plants. He randomly assigns 90 plants at the same stage of development to two treatment groups, 20oC or 35oC. After three months, he measures the weights of the plants and calculates the difference in mean weights of the plants for each temperature (35oC – 20oC).What is the appropriate inference procedure?

A shoe company wants to determine if the new tread on its top line of running shoes lasts longer than the original tread. The company recruits 50 runners for a study. Each runner will perform their typical workout wearing one shoe with the original tread on one foot and another shoe with the new tread on the other foot. The foot that wears the new type of tread will be decided by flipping a coin. After one month, the runner will wear the new type of tread on the opposite foot. At the end of the second month, the difference in tread wear (New – Original) will be calculated.

A company that sells hair-care products claims that a product that combines shampoo and conditioner works better than a shampoo and conditioner used separately. A researcher recruits 60 volunteers and pairs them according to age, hair color, and hair type. For each pair, the researcher flips a coin to determine which volunteers will use the shampoo/conditioner combination and which ones will use the separate shampoo and conditioner. After using the products for one month, the subjects are asked to rate their satisfaction with the hair products on a scale of 1–10 (1 = highly dissatisfied and 10 = highly satisfied). The mean difference in satisfaction ratings (Combined – Separate) is calculated.

A student wants to determine if the proportion of times a spun penny lands on heads is different from 0.5. She spins a penny 50 times and records the number of times it lands on heads.What is the appropriate inference procedure?

A biologist wants to determine if temperature affects the growth of plants. He randomly assigns 90 plants to the treatment groups, 20oC or 35oC. After three months, he measures the weights of the plants and calculates the difference in mean weight of the plants for each temperature (35oC – 20oC).What is the appropriate inference procedure?

A teacher has two large containers filled with blue, red, and green beads. She wants her students to estimate the difference in the proportion of red beads in each container.What type of sampling is described in this study?

A teacher has two large containers (A and B) filled with blue, red, and green beads, and claims the proportion of red beads is the same in each container. The students believe the proportions are different. Each student shakes the first container, selects 50 beads, counts the number of red beads, and returns the beads to the container. The student repeats this process for the second container. One student’s samples contained 10 red beads from the first container and 16 red beads from the second container. The student then calculated the difference in the proportions of red beads.