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 is equal to highly dissatisfied and 10 is equal to highly satisfied). The mean difference in satisfaction ratings open paren Combined minus Separate close paren is calculated. What is the appropriate procedure for testing the company’s claim?
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?
A student wants to estimate the proportion of times a spun penny will land on heads. She spins a penny 50 times and records the number of times it lands on heads. What is the appropriate inference procedure?
A company would like to know if one brand of dish detergent cleans better than another. Fifty dirty dishes are randomly selected and randomly divided into two groups. In one group, each dirty dish will be placed in a container of hot water with Brand A detergent and in the other group, each dirty dish will be placed in a container of hot water with Brand B detergent. What type of sampling is described in this study?
A biologist wants to determine if temperature affects the growth of plants. He randomly assigns 90 plants to the treatment groups, 20 times degree C or 35 times degree C After three months, he measures the weights of the plants and calculates the difference in mean weight of the plants for each temperature open paren 35 times degree C minus 20 times degree C close paren 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?
The mayor of a local town wants to determine if there is support for a certain proposal. The mayor’s assistant randomly selects 100 households and asks whether they would support the mayor’s proposal. Sixty responded that they would support it. What type of sampling is described in this study?
A company would like to estimate the effectiveness of two dish detergents using cleanliness ratings. Fifty dirty dishes are randomly selected and randomly divided into two groups. In one group, each dirty dish will be placed in a container of hot water with Brand cap A detergent and in the other group, each dirty dish will be placed in a container of hot water with Brand cap b detergent. The dishes will sit for two hours, and then the cleanliness of the dishes will be measured using a scale of 1 – 10 ( 1 is equal to the least clean and 10 is equal to most clean). The difference in mean cleanliness ratings for the two detergents open paren cap A minus cap b close paren will then be calculated. What is the appropriate inference procedure?
The mayor of a large town wants to determine if a majority of the households in the town support a proposal. The mayor’s assistant randomly selects 100 households and asks whether they would support the mayor’s proposal. Sixty households responded that they would. Is there evidence that a majority of the households would support the proposal? What is the appropriate inference procedure?
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