Question 21

A new investigational drug for restless leg syndrome is to be tested in three cities. Individuals at hospitals, clinics, and medical practices that are being seen for RLS are chosen to participate based on a computer algorithm that selects patient phone numbers. This study is an example of what type of sampling technique?

Select one:

a.

random

b.

cluster

c.

convenience

Question 22

Match the following to their descriptions:

A research study that examines the mean number of pounds loss in a weight loss clinic.

Answer 1

Choose...

A research study that compares the mean number of pounds loss between two different weight loss clinics.

Answer 2

Choose...

A research study that weighs individuals at the beginning of the weight loss program and measures the same individual at the end of the program and calculates the difference in weight for each individual.

Answer 3

Choose...

A research study that examines what percentage of individuals actually lost weight during the weight loss program.

Answer 4

Choose...

A research study that examines there is a difference in the percentage of individuals that have lost weight in clinic 1 versus in clinic 2.

Answer 5

Choose...

Question 23

Recall in our discussion of the normal distribution the research study that examined the blood vitamin D levels of the entire US population of landscape gardeners. The intent of this large-scale and comprehensive study was to characterize fully this population of landscapers as normally distributed with a corresponding population mean and standard deviation, which were determined from the data collection of the entire population.

Suppose you are now in a different reality in which this study never took place though you are still interested in studying the average vitamin D levels of US landscapers. In other words, the underlying population mean and standard deviation are now unknown to you. You obtain research funding to randomly sample 38 landscapers, collect blood samples, and send these samples to your collaborating lab in order to quantify the amount of vitamin D in the landscapers' blood. After anxiously awaiting your colleagues to complete their lab quantification protocol, they email you the following vitamin D level data as shown in the following table.

Subject Vitamin D

1 37.744

2 33.725

3 26.858

4 34.371

5 31.686

6 34.165

7 33.783

8 32.439

9 25.973

10 33.426

11 32.800

12 28.683

13 39.246

14 27.577

15 50.211

16 23.222

17 33.087

18 36.525

19 31.894

20 41.927

21 32.317

22 31.266

23 43.910

24 22.740

25 40.747

26 31.905

27 33.870

28 27.450

29 36.104

30 37.227

31 36.092

32 30.033

33 41.060

34 40.627

35 37.460

36 27.959

37 45.872

38 29.875

What is the estimated 95% confidence interval (CI) of the average blood vitamin D level of US landscapers in ng/mL?

Please note the following: 1) you might calculate a CI that is different from any of the multiple choice options listed below due to rounding differences, therefore select the closest match; 2) ensure you use either the large or small sample CI formula as appropriate; and 3) you may copy and paste the data into Excel to facilitate analysis.

Select one:

a.

32.2 to 36.0 ng/mL

b.

29.9 to 33.5 ng/mL

c.

28.2 to 31.9 ng/mL

d.

34.1 to 40.0 ng/mL

Question 24

Ethnicity, marital status, language, type of diet . . . these are examples of what type of variable?

Select one:

a.

Continuous Variables

b.

Ordinal Variables

c.

Dichotomous Variables

d.

Categorical Variables

Question 25

Recall in our discussion of the normal distribution the research study that examined the blood vitamin D levels of the entire US population of landscape gardeners. The intent of this large-scale and comprehensive study was to characterize fully this population of landscapers as normally distributed with a corresponding population mean and standard deviation, which were determined from the data collection of the entire population.

Suppose you are now in a different reality in which this study never took place though you are still interested in studying the average vitamin D levels of US landscapers. In other words, the underlying population mean and standard deviation are now unknown to you. Furthermore, you would like to collect data from US office workers to examine the difference between the average vitamin D levels of landscapers and office workers, which will reflect any occupational sun exposure differences as measured by blood vitamin D levels. You obtain research funding to sample at random 31 landscapers and 50 office workers, collect blood samples, and send these samples to your collaborating lab in order to quantify the amount of vitamin D in both groups' blood. After anxiously awaiting your colleagues to complete their lab quantification protocol, they email you the following vitamin D level data as shown in the following tables.

Table 1. Landscapers

Subject Vitamin D

1 51.697

2 49.831

3 48.101

4 45.917

5 52.461

6 57.849

7 58.529

8 53.175

9 51.939

10 52.982

11 50.992

12 55.848

13 44.738

14 57.440

15 56.513

16 58.257

17 58.354

18 58.012

19 52.461

20 53.247

21 50.426

22 51.975

23 51.233

24 52.708

25 58.917

26 53.658

27 55.348

28 55.010

29 53.537

30 49.306

31 55.019

Table 2. Office Workers

Subject Vitamin D

1 44.014

2 44.339

3 34.795

4 32.188

5 29.765

6 45.128

7 44.883

8 41.930

9 35.647

10 34.140

11 43.068

12 31.765

13 34.107

14 47.538

15 44.150

16 46.885

17 37.899

18 39.672

19 40.229

20 48.569

21 39.812

22 38.266

23 49.937

24 41.663

25 31.853

26 51.381

27 44.924

28 39.668

29 52.038

30 39.183

31 38.326

32 36.761

33 37.835

34 37.699

35 42.189

36 47.116

37 32.393

38 50.495

39 43.831

40 50.344

41 37.640

42 50.728

43 40.771

44 43.805

45 48.372

46 48.252

47 44.477

48 41.677

49 42.033

50 48.023

What is the estimated 95% confidence interval (CI) of the average difference in blood vitamin D levels between US landscapers and office workers in ng/mL? Assign groups 1 and 2 to be landscapers and office workers, respectively.

Please note the following: 1) in practice, you as the analyst decide how to assign groups 1 and 2 and subsequently interpret the results appropriately in the context of the data, though for the purposes of this exercise the groups are assigned for you; 2) you might calculate a CI that is different from any of the multiple choice options listed below due to rounding differences, therefore select the closest match; 3) ensure you use either the large or small sample CI formula as appropriate; and 4) you may copy and paste the data into Excel to facilitate analysis.

Select one:

a.

9.26 to 13.86 ng/mL

b.

7.87 to 12.20 ng/mL

c.

7.82 to 11.85 ng/mL

d.

9.81 to 15.66 ng/mL

Question 26

42% of mosquitos caught at random in any given field study carry malaria. If you conduct a study and capture 85 mosquitos, how many mosquitos infected with malaria would you expect to have in your mosquito-catching Mason jar out of all 85 mosquitos buzzing around? Round up to the nearest whole number if your calculation results in a number with decimal point values. For example, 0.2 rounds up to 1 and 74.25 rounds up to 75.

Answer:

Question 27

A research study of 15 children with a diagnosis of ADHD wish to assess whether the BMI of the children is correlated with degrees of hyperactivity in the child. The BMI of the 15 children in a study: 22, 23, 25, 24, 18, 27, 26, 29, 28, 31, 32, 28, 33, 28, 34. What is the mode of BMI of the children?

Select one:

a.

27.3

b.

28.0

c.

29.0

d.

24.5

Question 28

Previous research states, "no evidence currently exists supporting or refuting the use of electric fans during heat waves" in terms of mortality and illness. Counterintuitively, Public Health guidelines suggest not using fans during hot weather, with some research reporting the potential of fans accelerating body heating.

You decide to research further this seemingly contradictory guidance, hypothesizing that the true population proportion of heart and core temperature increases amidst higher ambient temperature and humidity levels is different than 36.6% and setting the level of significance at 10% for the formal hypothesis test. You randomly sample 41 participants based on your research funding and for 45 minutes, the study participants sit in a chamber maintained at a temperature of 108 degrees Fahrenheit (i.e., 42 degrees Celsius) and a relative humidity of 70%. At the end of the 45 minutes, you record for all participants if his/her heart and core temperature increased as compared to the start of the time period. The following table comprises the data you collect.

Subject Heart and Core Temperature Increased?

1 0

2 1

3 0

4 0

5 0

6 0

7 0

8 0

9 1

10 0

11 0

12 0

13 0

14 0

15 1

16 0

17 1

18 0

19 0

20 0

21 0

22 0

23 0

24 0

25 0

26 1

27 0

28 0

29 1

30 0

31 1

32 0

33 0

34 0

35 1

36 0

37 1

38 0

39 1

40 0

41 0

Per Step 4 of the 5-Steps to Hypothesis Testing, compute the test statistic using the appropriate test statistic formula.

Please note the following: 1) 0 and 1 are defined as no and yes, respectively, which is a typical coding scheme in Public Health; 2) you may copy and paste the data into Excel to facilitate analysis; and 3) do not round your numerical answer that you submit as the online grading system is designed to mark an answer correct if your response is within a given range. In other words, the system does not take into account rounding. On the other hand, rounding is preferable when formally reporting your statistical results to colleagues.

Answer:

Question 29

Recall in our discussion of the binomial distribution the research study that examined schoolchildren developing nausea and vomiting following holiday parties. The intent of this study was to calculate probabilities corresponding to a specified number of children becoming sick out of a given sample size. Recall also that the probability, i.e. the binomial parameter "p" defined as the probability of "success" for any individual, of a randomly selected schoolchild becoming sick was given.

Suppose you are now in a different reality, in which this binomial probability parameter p is now unknown to you but you are still interested in carrying out the original study described above, though you must first estimate p with a certain level of confidence. You obtain research funding to randomly sample 25 schoolchildren with an inclusion criterion that he/she must have recently attended a holiday party, and conduct a medical evaluation by a certified pediatrician. After anxiously awaiting your pediatrician colleague to complete her medical assessments, she emails you data contained in the following table.

Subject Nausea and Vomiting?

1 1

2 1

3 1

4 0

5 1

6 0

7 1

8 0

9 0

10 0

11 0

12 1

13 1

14 0

15 1

16 0

17 0

18 1

19 0

20 0

21 0

22 0

23 0

24 0

25 0

What is the estimated 95% confidence interval (CI) of the proportion of schoolchildren developing nausea and vomiting following holiday parties?

Please note the following: 1) 0 and 1 are defined as no and yes, respectively, which is a typical coding scheme in Public Health; 2) you might calculate a CI that is different from any of the multiple choice options listed below due to rounding differences, therefore select the closest match; and 3) you may copy and paste the data into Excel to facilitate analysis.

Select one:

a.

0.172 to 0.548

b.

0.146 to 0.630

c.

0.188 to 0.617

d.

0.144 to 0.608

Question 30

A research study wishes to examine the mean resting heart rate for 16 individuals among four different groups of exercises (evenly distributed to 4 individuals per group). The sum of the variability between groups is 792.69 and the sum of the variability within a group (error) is 207.75. Calculate the test statistic.

Select one:

a.

13.68

b.

14.55

c.

15.26

d.

15.98

Question 31

A research study examined the blood vitamin D levels of the entire US population of landscape gardeners. The population average level of vitamin D in US landscapers was found to be 47.68 ng/mL with a standard deviation of 4.002 ng/mL. Assuming the true distribution of blood vitamin D levels follows a Gaussian distribution, if you randomly select a landscaper in the US, what is the likelihood that his/her vitamin D level will be 55.19 ng/mL or more?

Answer:

Question 32

A grocery store carries the following items. There are two main categories of food - conventional and organic ingredients - and four food groups. The data are shown in the following table.

Food Groups

Food Categories Grains Fruits Vegetables Meat Total

Conventional 49 94 7 168 318

Organic 126 31 293 47 497

Total 175 125 300 215 815

If all of the items were accidentally displayed together without a sticker or label to mark their origin, what is the probability that you select an organic grain, fruit, or vegetable in your grocery basket? First compute for yourself the row (i.e., n1+, n2+), column (i.e., n+1, n+2, n+3, n+4), and overall (i.e., n++) totals, to aid in answering the question.

Answer:

Question 33

Suppose at random 43% of school children develop nausea and vomiting following holiday parties and that you conduct a study to examine this phenomenon, with a sample size of n=39. What is the probability that less than 13, or 33 or more children become sick?

Answer:

Question 34

A research study examined the effects of a new drug versus an old drug on hypertension. There were 172 people enrolled in the new drug trial, and 125 of them were hypertensive. For the old drug, 165 people were enrolled and of those, 76 were hypertensive. Was there a difference in the percentage of people who were hypertensive between the new drug and the old drug? Calculate the z, t, or chi-square test and choose the value in the answer below.

Select one:

a.

4.98

b.

5.36

c.

4.17

d.

5.89

Question 35

When the AIDS epidemic first broke out, a series of cases were published regarding rare syndromes and diseases not usually seen in the general population. These case studies included symptoms, dates, and general background information on the patients including gender, age, and ethnicity. This type of study uses what kind of statistics:

Select one:

a.

Descriptive

b.

Inferential

Question 36

A research study of 15 children with a diagnosis of ADHD wish to assess whether the BMI of the children is correlated with degrees of hyperactivity in the child. The BMI of the 15 children in a study: 22, 23, 25, 24, 18, 27, 26, 29, 28, 31, 32, 28, 33, 28, 34. What is the 25th quartile of BMI of the children?

Select one:

a.

27.3

b.

28.0

c.

29.0

d.

24.5

Question 37

Age, income, height, weight, blood pressure . . . these are examples of what type of variable?

Select one:

a.

Continuous Variables

b.

Ordinal Variables

c.

Dichotomous Variables

d.

Categorical Variables

Question 38

A grocery store carries the following items. There are two main categories of food - conventional and organic ingredients - and four food groups. The data are shown in the following table.

Food Groups

Food Categories Grains Fruits Vegetables Meat Total

Conventional 86 108 195 66 455

Organic 89 17 105 149 360

Total 175 125 300 215 815

If all of the conventional items were accidentally displayed together without a sticker or label to mark their origin, what is the probability that you select a conventional grain or fruit into your grocery basket? First compute for yourself the row (i.e., n1+, n2+), column (i.e., n+1, n+2, n+3, n+4), and overall (i.e., n++) totals, to aid in answering the question.

Answer:

Question 39

A research study wishes to examine the proportion of hypertensive individuals among three different groups of exercises: marathon runners, yoga, and CrossFit. Of the 78 marathon runners, 14 are hypertensive. Of the 63 yoga practitioners, 6 are hypertensive. And there are 16 hypertensive subjects among the 54 CrossFit athletes. What type of test statistic do you need to run for this type of analysis?

Select one:

a.

Chi-Square Test of Independence

b.

Chi-Square Goodness of Fit

c.

Z-test

d.

T-test

e.

F-test

Question 40

Depression severity, pain severity, cancer staging . . . these are examples of what type of variable?

Select one:

a.

Continuous Variables

b.

Ordinal Variables

c.

Dichotomous Variables

d.

Categorical Variables