5. If a statistically significant difference in blood pressure change at the end of a year for the

two activities was found, then:

a. It cannot be concluded that the difference in activity caused a difference in the change in

blood pressure because in the course of a year there are lots of possible confounding

variables.

b. Whether or not the difference was caused by the difference in activity depends on what

else the participants did during the year.

c. It cannot be concluded that the difference in activity caused a difference in the change in

blood pressure because it might be the opposite, that people with high blood pressure

were more likely to read a book than to walk.

d. It can be concluded that the difference in activity caused a difference in the change in

blood pressure because of the way the study was done.

6. What is one of the distinctions between a population parameter and a sample statistic?

a. A population parameter is only based on conceptual measurements, but a sample statistic

is based on a combination of real and conceptual measurements.

b. A sample statistic changes each time you try to measure it, but a population parameter

remains fixed.

c. A population parameter changes each time you try to measure it, but a sample statistic

remains fixed across samples.

d. The true value of a sample statistic can never be known but the true value of a population

parameter can be known.

7. A magazine printed a survey in its monthly issue and asked readers to fill it out and send it

in. Over 1000 readers did so. This type of sample is called

a. a cluster sample.

b. a self-selected sample.

c. a stratified sample.

d. a simple random sample.

8. Which of the following would be most likely to produce selection bias in a survey?

a. Using questions with biased wording.

b. Only receiving responses from half of the people in the sample.

c. Conducting interviews by telephone instead of in person.

d. Using a random sample of students at a university to estimate the proportion of people

who think the legal drinking age should be lowered.

9. Which one of the following variables is not categorical?

a. Age of a person.

b. Gender of a person: male or female.

c. Choice on a test item: true or false.

d. Marital status of a person (single, married, divorced, other)

. Which of the following is the explanatory variable in this study?

a. Exercise

b. Lung capacity

c. Smoking or not

d. Occupation

2. Which of the following is a confounding variable in this study?

a. Exercise

b. Lung capacity

c. Smoking or not

d. Occupation

This scenario applies to Questions 3 to 5: A randomized experiment was done by randomly

assigning each participant either to walk for half an hour three times a week or to sit quietly

reading a book for half an hour three times a week. At the end of a year the change in

participants' blood pressure over the year was measured, and the change was compared for the

two groups.

3. This is a randomized experiment rather than an observational study because:

a. Blood pressure was measured at the beginning and end of the study.

b. The two groups were compared at the end of the study.

c. The participants were randomly assigned to either walk or read, rather than choosing

their own activity.

d. A random sample of participants was used.

4. The two treatments in this study were:

a. Walking for half an hour three times a week and reading a book for half an hour three

times a week.

b. Having blood pressure measured at the beginning of the study and having blood pressure

measured at the end of the study.

c. Walking or reading a book for half an hour three times a week and having blood pressure

measured.

d. Walking or reading a book for half an hour three times a week and doing nothing.

This graph shows the birth and death rates in Europe over time. Choose the valid conclusion from the graph. All of the choices are true. The population growth rate has stayed stable (remained similar) over time. The annual net rate of growth (birth rate - death rate) is decreasing over time. This population is declining rapidly.14. | Demographics: Birth Rate and Death Rate In the following data pairs, A represents birth rate and B represents death rate per 1000-resident population. The data are paired by counties in the Midwest. A random sample of 16 coun- ties gave the following information (Reference: County and City Data Book, U.S. Department of Commerce): A: 12.7 13.4 12.8 12.1 11.6 11.1 14.2 15.1 B: 9.8 14.5 10.7 14.2 13.0 12.9 10.9 10.0 A: 12.5 12.3 13.1 15.8 10.3 12.7 11.1 15.7 B: 14.1 13.6 9.1 10.2 17.9 11.8 7.0 9.2 Do the data indicate a difference (either way) between population average birth rate and death rate in this region? Use a = 0.01.Question 1. You are studying an endangered population of orchids, for which the birth rate b = 0.20 births per individual per year and the death rate d = 0.18 deaths per individual per year. The current population size (No) is 50 plants. A. A new shopping mall is planned that will eliminate part of the orchid habitat and reduce the current population to 25 individuals. Given that the probability of extinction for a population is: Pextinction = (d/b)No (where b and d = birth and death rates and No = initial population size), estimate the potential effect of the proposed development on the probability of extinction for this population. State your answer in words. Show your work. B. The logistic growth model accounts for the idea that in the real world, resource availability ultimately limits population growth. Is resource availability a density-dependent or density- independent factor in such a model? Explain.70 Doubling time =- % growth rate Population growth = births - deaths + immigration - emigration late the doubling time for each of the following cher opulation A has an intrinsic growth rate of 5.5%. 70 5. 5/ A population that adds 18 individuals for every 1,000 individuals in the population. Population B has 26 births and 11 deaths per 1,000 individuals per year. 26-61 Population C has a birth rate of 4.5% and a death rate of 2.5%