Question

unit 3 test

1. a large simple random sample of people aged nineteen to thirty living in the state of colorado was surveyed to determine which of two mp3 players just developed by a new company was preferred. to which of the following populations can the results of this survey be safely generalized?

(a) only people aged nineteen to thirty living in the state of colorado who were in this survey
(b) only people aged nineteen to thirty living in the state of colorado
(c) all people living in the state of colorado
(d) only people aged nineteen to thirty living in the united states
(e) all people living in the united states

1. an experiment was designed to investigate the relationship between the dosage of a certain migraine medication and the amount of time until relief from the headache was experienced. four dosages in milligrams (mg) - 2.5, 5.0, 7.5, and 10 - of the medication were used. the 20 participants in the experiment were known to experience migraines. each participant was randomly assigned one of the four dosages. when the participants experienced a migraine, they took the assigned medication and recorded the number of minutes it took to experience relief from the headache. the mean number of minutes it took each group to experience relief was compared.

what were the experimental units in the experiment?
(a) the number of minutes to experience relief
(b) the mean number of minutes it took each group to experience relief
(c) the four dosages
(d) the 20 participants
(e) the relationship between the dosage and the amount of time

1. each person in a simple random sample of 2,000 received a survey, and 317 people returned their survey. how could nonresponse cause the results of the survey to be biased?

(a) those who did not respond reduced the sample size, and small samples have more bias than large samples.
(b) those who did not respond caused a violation of the assumption of independence.
(c) those who did not respond were indistinguishable from those who did not receive the survey.
(d) those who did not respond represent a stratum, changing the simple random sample into a stratified random sample.
(e) those who did respond may differ in some important way from those who did not respond.

1. a total of 13 distinct groups, but with each group similar to the other groups, participated in a craft fair. to investigate how satisfied the participants were with the fair, the fair director conducted a survey. the director randomly selected 5 of the groups participating in the fair and surveyed all members of the selected groups.

which statement best describes the sampling method used by the director?
(a) it was convenience sampling, because participants from each group were easy to contact.
(b) it was simple random sampling, because the participants were selected at random.
(c) it was stratified random sampling, because the director ensured that members from each group were selected.
(d) it was cluster sampling, because the sample consisted of all members of the 5 randomly selected groups.
(e) it was systematic random sampling, because the director selected exactly 5 groups.

Explanation:

Question 4

When generalizing survey results, the population should match the sample's characteristics. The sample is people aged nineteen - thirty in Colorado. So the results can be generalized to the entire population of people aged nineteen - thirty in Colorado (not just those in the survey). Options C, D, and E have broader or incorrect populations.

Experimental units are the entities on which the experiment is performed. Here, the experiment is performed on the 20 participants (they are assigned dosages and their relief times are measured). The number of minutes (A) is a response variable, the mean number of minutes (B) is a summary statistic, the four dosages (C) are treatments, and the relationship (E) is what is being investigated.

Non - response bias occurs when those who respond may differ in important ways from those who don't. Option A is wrong as non - response is about bias not sample size. Option B is incorrect as it's not about sample size assumption. Option C is wrong as there's no independence assumption violation here. Option D is wrong as non - responders are not part of the sample in a simple random sample.

Answer:

B. Only people aged nineteen to thirty living in the state of Colorado

Question 5