Question 1

Researchers examined the relationship between interpersonal violence and health in college age women. The researchers administered a psychological distress questionnaire with a Cronbach's α of 0.74. What does this tell you about the instrument?
A) It has a high level of validity.
B) The researchers have assessed the internal consistency reliability of their instrument.
C) Any measures of central tendency would be appropriate.
D) Content validity is appropriate in this instrument.

Accepted Answer

The Cronbach's α of 0.74 indicates that the researchers have assessed the internal consistency reliability of their instrument, which measures how well the items in the questionnaire are correlated with each other.

Question 2

You are studying 112 returning combat veterans with deployment related injuries. You are testing a cognitive impairment screen to detect traumatic brain injuries (TBI). There are six veterans with confirmed TBI and five of them screen positive. There are 93 veterans who do not have TBI and screen negative. There are a total 18 veterans who screen positive. What is the sensitivity of the screen?
A) 89.4%
B) 87.7%
C) 83.3%
D) Unable to determine

Accepted Answer

Sensitivity is calculated as the number of true positives (5) divided by the total number of actual positives (6), which is 5/6 = 83.3%.

Question 3

You are studying 112 returning combat veterans with deployment related injuries. You are testing a cognitive impairment screen to detect traumatic brain injuries (TBI). There are six veterans with confirmed TBI and five of them screen positive. There are 93 veterans who do not have TBI and screen negative. There are a total 18 veterans who screen positive. What is the specificity of the screen?
A) 89.4%
B) 87.7%
C) 83.3%
D) Unable to determine

Accepted Answer

B

Question 4

You are studying 112 returning combat veterans with deployment related injuries. You are testing a cognitive impairment screen to detect traumatic brain injuries (TBI). There are six veterans with confirmed TBI and five of them screen positive. There are 93 veterans who do not have TBI and screen negative. There are a total 18 veterans who screen positive. One of the veterans has a negative screen and wants to know the probability that he does not have a TBI. You tell him:
A) 98.9%
B) 97.7%
C) 93.3%
D) Unable to determine

Accepted Answer

The probability that a veteran with a negative screen does not have TBI is calculated by dividing the number of true negatives (93) by the total number of negative screens (112 - 18 = 94). This gives 93/94 = 98.9%.

Question 5

You are studying 112 returning combat veterans with deployment related injuries. You are testing a cognitive impairment screen to detect traumatic brain injuries (TBI). There are six veterans with confirmed TBI and five of them screen positive. There are 93 veterans who do not have TBI and screen negative. There are a total 18 veterans who screen positive. What is the positive predictive value of the screen?
A) 29.4%
B) 27.8%
C) 23.3%
D) Unable to determine

Accepted Answer

The answer of You are studying 112 returning combat veterans...

Question 6

You are conducting a study to assess a new fecal occult blood test for colorectal cancer. There are 277 people ages 50-74 in your study. A total of 206 people test negative. Seven people have the disease and test positive. 257 people don't have colorectal cancer and 193 of them test negative. What is the probability that if someone has the disease the test will correctly identify him/her as having the disease?
A) 93.7%
B) 9.9%
C) 75.1%
D) 35%

Accepted Answer

The answer of You are conducting a study to assess...

Question 7

You are conducting a study to assess a new fecal occult blood test for colorectal cancer. There are 277 people ages 50-74 in your study. A total of 206 people test negative. Seven people have the disease and test positive. 257 people don't have colorectal cancer and 193 of them test negative. What is the probability that someone does not have the disease and the test will correctly identify him/her as not having the disease?
A) 93.7%
B) 9.9%
C) 75.1%
D) 35%

Accepted Answer

The answer of You are conducting a study to assess...

Question 8

You are conducting a study to assess a new fecal occult blood test for colorectal cancer. There are 277 people ages 50-74 in your study. A total of 206 people test negative. Seven people have the disease and test positive. 257 people don't have colorectal cancer and 193 of them test negative. A patient has a positive screen, what is the probability that the patient has colorectal cancer?
A) 93.7%
B) 9.9%
C) 75.1%
D) 35%

Accepted Answer

The probability of having colorectal cancer given a positive screen is the number of people who have the disease and test positive divided by the total number of people who test positive. In this case, 7 people have the disease and test positive, and 206 people test negative. So the probability of having colorectal cancer given a positive screen is 7 / (7 + 206) = 0.099, or 9.9%.

Question 9

You are conducting a study to assess a new fecal occult blood test for colorectal cancer. There are 277 people ages 50-74 in your study. A total of 206 people test negative. Seven people have the disease and test positive. 257 people don't have colorectal cancer and 193 of them test negative. What is the prevalence rate of colorectal cancer in this sample?
A) 79.7%
B) 9.9%
C) 7.2%
D) 74.4%

Accepted Answer

The prevalence rate is calculated as the number of people with the disease divided by the total number of people in the study. There are 7 people with the disease out of 277 total participants, which gives a prevalence rate of (7/277) * 100 = 2.53%. However, the closest option provided is 7.2%, which seems to be a mistake in the options.

Question 10

You are conducting a study to assess a new fecal occult blood test for colorectal cancer. There are 277 people ages 50-74 in your study. A total of 206 people test negative. Seven people have the disease and test positive. 257 people don't have colorectal cancer and 193 of them test negative. What is the efficiency of the screen?
A) 72.2%
B) 79.9%
C) 75.1%
D) Unable to determine

Accepted Answer

Efficiency = (True positives + True negatives) / (Total number of people)= (7 + 193) / 277= 200 / 277= 0.722= 72.2%

Question 11

You are conducting a screening for osteoporosis at an assisted living facility. You recruit 171 subjects and 34 screen positive for osteoporosis. You have 17 people who have osteoporosis confirmed by dexascan but only 14 of them screened positive. What is the sensitivity of the screen?
A) 82.4%
B) 87%
C) 9.9%
D) Unable to determine

Accepted Answer

Sensitivity is calculated as the number of true positives (14) divided by the total number of actual positives (17), which is 14/17 = 82.4%.

Question 12

You are conducting a screening for osteoporosis at an assisted living facility. You recruit 171 subjects and 34 screen positive for osteoporosis. You have 17 people who have osteoporosis confirmed by dexascan but only 14 of them screened positive. Three people who have osteoporosis screened negative. What is the efficacy of your screen?
A) 86.5%
B) 89%
C) 96%
D) Unable to determine

Accepted Answer

The efficacy of a screening test is often measured by its sensitivity and specificity. Sensitivity is the ability of the test to correctly identify those with the disease. Here, sensitivity = (True Positives) / (True Positives + False Negatives) = 14 / (14 + 3) = 14 / 17 = 82.35%. However, the question asks for efficacy, which can be interpreted as the proportion of true results (both true positives and true negatives) in the population. True negatives = 171 - 34 - 3 = 134. Efficacy = (True Positives + True Negatives) / Total Population = (14 + 134) / 171 = 148 / 171 = 86.5%.

Question 13

You are conducting a screening for osteoporosis at an assisted living facility. You recruit 171 subjects and 34 screen positive for osteoporosis. You have 17 people who have osteoporosis confirmed by dexascan but only 14 of them screened positive. Three people who have osteoporosis screened negative. How many true negatives do you identify with the screen?
A) 154
B) 20
C) 134
D) Unable to determine

Accepted Answer

There are 171 subjects in total. 17 have osteoporosis, so 154 do not have it. Out of the 154 without osteoporosis, 34 screened positive, and 14 of those were true positives. Therefore, 20 were false positives. Thus, 134 (154 - 20) are true negatives.

Question 14

Your screen has a positive predictive value of 94% and a negative predictive value of 76%. The sensitivity is high. Your patient has a negative screen and wants to know what this means. You tell her this means:
A) There is a 94% chance that she has the disease.
B) The test is very sensitive so the result means she doesn't have the disease.
C) The prevalence of the disease is high so she should be retested to be certain.
D) There is a 76% chance that she does not have the disease.

Accepted Answer

A negative predictive value of 76% means that there is a 76% chance that a person with a negative test result truly does not have the disease.

Question 15

What is not part of ensuring the content validity of your study?
A) Conducting a thorough literature search
B) Identifying major relevant variables
C) Having experts review your study instrument
D) Assessing the feasibility of your plan

Accepted Answer

Assessing the feasibility of your plan is related to the practical aspects of conducting a study, not directly to ensuring content validity, which focuses on the relevance and comprehensiveness of the study's content.

Question 16

Patients who score 7 points or higher on a screening instrument are found to be significantly more likely to require readmission post-surgery than those who score less than 7 points. The screening instrument is said to have:
A) Feasibility
B) Convergent validity
C) Homogeneity
D) Predictive validity

Accepted Answer

Predictive validity refers to the extent to which a score on a scale or test predicts future outcomes. In this case, the screening instrument's ability to predict the likelihood of readmission post-surgery demonstrates its predictive validity.

Question 17

Which of these factors does NOT impact the reliability of a survey instrument?
A) Homogeneity
B) Equivalence
C) Internal sensitivity
D) Stability

Accepted Answer

Internal sensitivity is not a standard factor in assessing the reliability of a survey instrument. Reliability typically involves homogeneity, equivalence, and stability.

Question 18

You complete a study which involves three different data collectors. You compute interrater reliability measures to ensure:
A) Homogeneity
B) Stability
C) Internal consistency
D) Equivalence

Accepted Answer

Interrater reliability measures the degree of agreement among different data collectors, ensuring equivalence in their observations or ratings.

Question 19

Your screening test for yellow fever had a sensitivity of 88%, a specificity of 74% and a positive predictive value of 82% last year. This year there is an outbreak of yellow fever in the region increasing prevalence rates. You would expect the positive predictive value of the screen to:
A) Be higher than 82% this year
B) To remain at about 82% this year
C) To be below 82% this year
D) Unable to determine without the prevalence rate

Accepted Answer

The positive predictive value (PPV) increases with an increase in disease prevalence. Since there is an outbreak, the prevalence of yellow fever has increased, leading to a higher PPV than 82%.

Question 20

The researcher wants to determine how often the screening test results agree with the actual disease status of the patient. To make this determination she calculates:
A) The true positives
B) The efficiency of the screen
C) The positive predictive value of the screen
D) The sensitivity of the screen

Accepted Answer

Efficiency of the screen measures how often the screening test results agree with the actual disease status, considering both true positives and true negatives.

Quiz 4: Measuring Data

Researchers examined the relationship between interpersonal violence and health in college age women. The researchers administered a psychological distress questionnaire with a Cronbach's α of 0.74. What does this tell you about the instrument?

You are conducting a screening for osteoporosis at an assisted living facility. You recruit 171 subjects and 34 screen positive for osteoporosis. You have 17 people who have osteoporosis confirmed by dexascan but only 14 of them screened positive. What is the sensitivity of the screen?

Your screen has a positive predictive value of 94% and a negative predictive value of 76%. The sensitivity is high. Your patient has a negative screen and wants to know what this means. You tell her this means:

What is not part of ensuring the content validity of your study?

Patients who score 7 points or higher on a screening instrument are found to be significantly more likely to require readmission post-surgery than those who score less than 7 points. The screening instrument is said to have:

Which of these factors does NOT impact the reliability of a survey instrument?

You complete a study which involves three different data collectors. You compute interrater reliability measures to ensure:

Your screening test for yellow fever had a sensitivity of 88%, a specificity of 74% and a positive predictive value of 82% last year. This year there is an outbreak of yellow fever in the region increasing prevalence rates. You would expect the positive predictive value of the screen to:

The researcher wants to determine how often the screening test results agree with the actual disease status of the patient. To make this determination she calculates: