HIM 3200 Epidemiology & Biostatistics Midterm

A researcher has collected the blood samples of 29 individuals and found that the mean hemoglobin concentration for the sample of individuals is 13.9 grams per deciliter and the standard deviation is 1.43 grams per deciliter. Calculate a 95% confidence interval for the mean hemoglobin concentration for the population.

(13.36, 14.44)

On May 1, 2010, the number of residents of Oklahoma who had been diagnosed with asthma at any time during their life was A. The population on June 30, 2010, was B. During the same year, the number of new cases of asthma was C. Which of the following expressions represents the point prevalence (percentage) of asthma?

(A/B) x 100

Assuming you obtained a random sample of blood glucose levels from 32 individuals from a population and the mean of the population is 120 and the standard deviation of the sample is 15, calculate the probability that the mean blood glucose levels for the sample population will be above 127.

.0041

Calculate the point estimate for a phase three clinical trial for a medication used to treat psoriasis, if 1790 patients show improvement of their psoriasis symptoms and 448 individuals did not show improvement of their psoriasis symptoms.

.7998

Assume a researcher wanted to know the probability that an individual's systolic blood pressure would fall below 157 and the researcher found that the z-score corresponding to the 157 systolic blood pressure is 1.62. What is the probability that a random individual's systolic blood pressure would fall below 157?

.9474

A large population health study which included 4,000 participants found a mean blood glucose of 110.2 with a standard deviation of 29.5. What is the upper confidence interval for the mean blood glucose?

111.1142

A simple random sample of 25,000 individuals are surveyed in order to determine the prevalence of individuals that contracted the flu in the past year. Assuming 4,250 individuals indicated they had been diagnosed with the flu at some point in the past year, what is the prevalence of flu for the past year, as indicated from the survey participants?

17.0%

We have a headache medication that is known to be effective in 70% of patients who take it. If we give the medication to 10 patients, what is the probability that exactly 7 of them will report relief?

26.68

What is the standard deviation of the following group of numbers: 85, 90, 150, 170, 94, 63, 92, 156, 87, 102, 116, 65, 145, 100, 72

34.1095

The table below shows counts for cases of influenza in the state of Utah. In 2016 the Utah population was 3,054,806. Assuming that the influenza data below is from 2016, what is the cumulative incidence of influenza per 100,000?

44.1926

Over the past year a group of family practice physicians have seen 3,500 boys, 4,200 girls, 7,700 pediatric patients total. The physicians want to select pediatric patients for a study using a simple random sample. What is the probability that they will select a boy from their population of pediatric patients?

45.5000

A population health survey was conducted to evaluate the prevalence of select chronic conditions. Obesity was one of these conditions. There were 4,000 respondents to the survey and 1,778 of them reported being obese. What is the Upper limit of the confidence interval? Remember: confidence intervals are reported (upper bound, lower bound) you just need to submit the upper bound limit. Hint: you must calculate the rate before you can calculate the confidence interval.

46.0000

Over the past year a group of family practice physicians have seen 3,500 boys, 4,200 girls, 7,700 pediatric patients total. The physicians want to select pediatric patients for a study using a simple random sample. What is the probability that they will select a girl from their population of pediatric patients?

54.5000

What is the interquartile range (IQR) of the following group of numbers: 85, 90, 150, 170, 94, 63, 92, 156, 87, 102, 116, 65, 145, 100, 72

60.0000

A number of patients have been admitted to a particular hospital with similar symptoms and the cause of the illness is unknown. Which type of study design would be most helpful in determining the cause of the illness?

A case series

Misclassification bias is most likely to be observed in which study type?

A case-control study

Whether a contaminated food such as tomatoes caused an outbreak of gastrointestinal disease is a simple example of:

A casual association

A researcher is interested in determining the current prevalence of rheumatoid arthritis in the United States. Which type of study would be most useful in estimating the prevalence of rheumatoid arthritis in the United States?

A cross-sectional survey

The measure of uncertainty in a biostatistician's calculation of a particular outcome that may result from using a subset of the population to estimate the actual likelihood of the event occurring in the population as a whole is referred to by what statistical term?

A margin of error

The systematic and continuous gathering of information about the occurrence of diseases and other health phenomena is known as:

A public health surveillance

A subset of the population of interest is often referred to by what statistical term?

A sample of individuals

According to the Generic Contingency table, the letter of the cell that shows that the exposure is present and disease is absent is:

B

Marital status is best defined as which of the following types of variables?

Categorical variable

Variations in infectious and chronic diseases from one country to another may be attributed to:

Climate Access to health care Cultural factors

Some examples of surveillance systems include those for:

Communicable and infections diseases Noninfectious diseases Risk factors for chronic diseases

A range of values that with a certain degree of probability contain the population parameter is known as a:

Confidence interval estimate

A novice researcher noted that during summertime there is a positive association between the increase in ice cream sales and the increase in the number of drownings; however, there is no logical explanation for why ice cream sales would be responsible for the increased incidence of drowning. What phenomenon likely explains this type of observation?

Confounding

Variation in the occurrence of diseases and other health outcomes in populations relates most closely to:

Distribution

Bubonic plague is a viral disease caused by Yersinia pestis.

False

True or False? A sufficient cause is not sufficient by itself to produce the effect.

False

True or False? Intention-to-treat analysis for a study is only conducted among individuals who fully complied with a study's protocols.

False

True or False? Relative risk is an ideal form of measurement for a retrospective study design because it allows researchers to recruit both individuals with the outcome of interest and individuals without the outcome of interest, then match individuals from each of the respective groups to individuals of the other group in order to determine if a specific exposure caused the outcome of interest.

False

True or False? Secondary prevention is directed toward the later stages of pathogenesis and involves programs for restoring the patient's optimal functioning.

False

True or False? The Behavioral Risk Factor Surveillance System (BRFSS) is an example of an ongoing case-control study.

False

True or False? The data collected in a biostatistics study can be applied to any population regardless of race, class, and socioeconomic status.

False

True or False? The probability of an individual developing prostate cancer is independent of the sex of the individual.

False

True or False? The standard deviation of any data set is the equivalent of the sample variance of the data set squared.

False

Examples of information collected by fetal death certificates include:

Name Disposition Congenital Anomalies

The process of defining measurement procedures for the variables used in a study is:

Operationalization

A study is being conducted to determine the prevalence of lung cancer in a population and the researchers want to note the frequency of each particular stage of cancer among the members of the population who have lung cancer; in this case the stage of cancer is best defined as which of the following types of variables?

Ordinal variable

Urban diseases and causes of mortality are more likely to be those associated with:

Person-to-person contact

Gradual changes in the frequency of diseases over long periods are known as:

Secular trends

Using health-related data that precede diagnosis and signal a sufficient probability of a case or an outbreak to warrant further public health response is known as:

Syndromic surveillance

For which of the following criteria do epidemiologists need to observe the cause before the effect?

Temporality

Those members of the population who are capable of developing a disease or condition are known as:

The population at risk

Assume a researcher wants to compare the mean Alanine Aminotransferase (ALT) levels in two populations, individuals who drink alcohol and individuals who do not drink alcohol. The mean ALT levels for the individuals who do not drink alcohol is 32 with a standard deviation of 14, and 37 individuals were in the sample. The mean ALT levels for individuals who drink alcohol is 69 with a standard deviation of 19, and 38 individuals were in the sample. Construct and interpret a 95% confidence interval demonstrating the difference in means for those individuals who drink alcohol when compared to those who do not drink alcohol.

The researchers are 95% confident that the true mean difference in ALT values between the population of drinkers and population of non-drinkers is between 24.41 and 39.59.

Assume researchers are trying to find out the mean concentration levels of a specific drug in a population of individuals' blood during a clinical trail. The researchers find that the sample population (n=100) has a mean concentration of 6.7 mcg/mL with a standard deviation of 1.3 mcg/mL. Calculate a 95% confidence interval for the mean concentration level of the medication for the population's blood and interpret it.

The researchers are 95.0% confident the true mean concentration of medication in the population's blood is between 6.445 mcg/mL and 6.955 mcg/mL.

Researchers have conducted a study and determined that the relative risk for developing a cold for individuals taking vitamin C is 0.47 when compared to the number of participants in the study who developed a cold while not taking vitamin C. This is an indication of which of the following?

This indicates that the individuals taking vitamin C were 53% less likely to catch a cold and that taking vitamin C has a protective effect, making them less likely to catch a cold.

Which of the following is not considered a use of epidemiology?

To provide health care services to specific individuals

Alexander Fleming discovered the antimicrobial properties of Penicillium notatum.

True

True or False? A necessary cause is sufficient by itself to produce the effect.

True

True or False? A researcher compares the BMI of two populations of individuals from different socioeconomic backgrounds and finds that the proportion of individuals considered obese and from a poor background is .37 ( n = 112), and the proportion of individuals considered obese and from an affluent background is .27 ( n = 87); a 95% confidence interval for the risk difference for obesity among members of the poor population compared to the affluent population is (-0.03, 0.23).

True

True or False? A test used to measure the concentration of inflammatory markers in an individual's blood is being researched. Assuming the test quantifies the concentration of the inflammatory markers in the blood and there are an infinite number of outcome possibilities, a study would likely demonstrate that the inflammatory markers for the population follow a normal, or non-normal, distribution pattern, depending on the results obtained from the study.

True

True or False? An active-control trial is the best option for researchers hoping to test a newly devised therapy for a life-threatening illness among individuals with the illness, when a previously devised treatment is available for the illness.

True

True or False? Before conducting a confidence interval for the mean difference between two independent samples, a researcher should check to make sure the ratio between both sample's variance is between 0.5 and 2.0.

True

True or False? Descriptive epidemiology characterizes health according to person, place, and time.

True

True or False? Extremely rare side effects of medications studied in clinical trials are more likely to be observed in cohort studies conducted during post marketing-surveillance because of the limited number of participants in clinical trials.

True

True or False? If a study utilizes a simple random sampling method, that means each member of the population of interest was equally likely to be selected as a study participant.

True

True or False? Oftentimes it is more difficult to establish a relationship between a particular disease outcome and a risk factor among older adults because they also have other risk factors for disease.

True

True or False? Screening for disease provides only preliminary information that needs to be followed by diagnostic information.

True

True or False? The maternal mortality rate encompasses maternal deaths that result from causes associated with pregnancy.

True

True or False? The medical examiner or coroner completes and signs the death certificate if the cause of death was an accident, suicide, or homicide or if the attending physician is unavailable.

True

True or False? The more spread out the points on a scatter plot are, with respect to the straight line of best fit through them, the stronger the association between the variables.

True

True or False? The wash-out period is included in a crossover trial so that any therapeutic effects of the first treatment are removed, prior to the administration of the second treatment.

True

Longitudinal cohort studies that produce data measured in person-time are particularly subject to which of the following forms of statistical anomaly?

Type 1 censoring

Sensitivity and specificity of a screening test refer to its:

Validity

Which cell in the table represents false positives?

c