Research Methods EXAM 2
What is the best statistical test to use to answer the following research question: "does body weight differ between freshman, sophomore, junior, and senior students at UC?"
ANOVA
The research study reviewed in Module 8, Lecture 2 (Chuang, 2006) compared outcomes between cardiac rehab patients who performed treadmill training with virtual reality (VR group) to those who performed treadmill training without virtual reality (non-VR group). 12 subjects were randomized to each group. Both groups received cardiac rehab that consisted of 30 min treadmill training 2x/week for 3 months. Randomization was performed by having each subject draw a ball from a box (Ball A=non-VR, and Ball B=VR). Investigators were not involved in this randomization. During the study, 4 subjects were lost to follow up, resulting in 20 subjects completing the study. Refer to the Tables and Figures in Chuang to answer the question, How many subjects in the VR group completed the study?
24
The statistical test (type of analysis) you would use to analyze data with an independent variable that is categorical with three categories, and a dependent variable that is continuous and normally distributed is...
ANOVA
A new questionnaire has been created to evaluate physical stress at work and the questions seem to make sense. A. Face validity B. Expert validity C. Construct validity D. Criterion validity - predictive validity E. Criterion validity - concurrent validity
A. Face validity
Chuang et al (2006) compared outcomes between cardiac rehab patients who performed treadmill training with virtual reality (VR group) versus those who performed treadmill training without virtual reality (non-VR group). 24 subjects were randomized to one of two groups: 1) VR group (n=12), or 2) non-VR group (n=12). Study design was a randomized control trial. All subjects received cardiac rehab (including 30 min of treadmill training) 2x/week for 3 months. There were no significant differences between groups in age, body mass index, V02max (oxygen capacity) or months since cardiac surgery. Choose the best answer below. a. Although randomization is the accepted way to "distribute" subjects into groups, it does not always result in "equal" characteristics between groups. b. Randomization will always ensure that baseline characteristics are similarly distributed between groups. c. Although randomization cannot guarantee that baseline characteristics will be similarly distributed between groups, it does increase the probability of similar distribution of baseline characteristics.
Although randomization cannot guarantee that baseline characteristics will be similarly distributed between groups, it does increase the probability of similar distribution of baseline characteristics.
A new questionnaire to evaluate spasticity in persons with stroke has been sent to experts in the field and has been revised based on their input A. Face validity B. Expert validity C. Construct validity D. Criterion validity - predictive validity E. Criterion validity - concurrent validity
B. Expert validity
Pearson
Both X and Y are normally distributed continuous variables
The number of push-ups a person can do reflects the operational definition of strength A. Face validity B. Expert validity C. Construct validity D. Criterion validity - predictive validity E. Criterion validity - concurrent validity
C. Construct validity
Choose the correct statistical test for this analysis: Does smoking status (yes, no) differ among adults by high school graduation status (high school diploma versus did not graduate from high school)?
Chi-square analysis
The number of push-ups a person can do reflects the operational definition of strength. What type of validity does this statement represent?
Construct validity
The Berg Balance Scale of <45 predicts a future fall among older adults. What type of validity does this statement represent?
Criterion validity - predictive validity
The Berg Balance Scale of <45 predicts a future fall among older adults. A. Face validity B. Expert validity C. Construct validity D. Criterion validity - predictive validity E. Criterion validity - concurrent validity
D. Criterion validity - predictive validity
A study was done to compare the effects of 8 weeks of meditation versus 8 weeks aerobic exercise on reducing stress in college students. 20 students were randomized to either 1) meditation or 2) exercise. The null hypothesis was: there will be no difference in stress between the groups after 8 weeks of treatment. The published article didn't have a sample size calculation in the Methods section. The results showed no difference in stress between the groups after 8 weeks of treatment. The article did not include a sample size calculation in the Methods article. Which section of the article would you most likely find the authors mention the possibility of the study being limited by a small sample size? a. Background/Introduction b. Methods c. Results d. Discussion
Discussion
Chuang et al (2006) compared outcomes between cardiac rehab patients who performed treadmill training with virtual reality (VR group) versus those who performed treadmill training without virtual reality (non-VR group). 24 subjects were randomized to one of two groups: 1) VR group (n=12), or 2) non-VR group (n=12). Study design was a randomized control trial. All subjects received cardiac rehab (including 30 min of treadmill training) 2x/week for 3 months. Randomization was performed by "lottery" where each subject (blindly) picked a ball from a box that originally contained 24 balls (12 of ball A=non-VR group, and 12 of ball B=VR group). Investigators were not involved in this randomization. Choose the best answer below. a. Subjects were masked (blinded) to group assignment. b. The research coordinators who performed the treadmill training were masked (blinded) to group assignment. c. Even though group assignment was randomized, in this type of study it is not possible to truly mask the subject or investigator conducting the training.
Even though group assignment was randomized, in this type of study it is not possible to truly mask the subject or investigator conducting the training.
A new questionnaire to evaluate spasticity in persons with stroke has been sent to experts in the field and has been revised based on their input. What type of validity does this statement represent?
Expert validity
A new questionnaire has been created to evaluate physical stress at work and the questions make sense to the research team. What type of validity does this statement represent?
Face validity
Standardized effect sizes of 0.90 are considered small.
False
The following table is adapted from: Njølstad I, Arnesen E, Lund-Larsen PG.Smoking, serum lipids, blood pressure, and sex differences in myocardial infarction. A 12-year follow-up of the Finnmark Study. Circulation. 1996 Feb 1;93(3):450-6. The table shows Rate Ratios and 95% confidence intervals (CI) of myocardial infarction by smoking status. Smoking Status Risk of Myocardial Infarction Rate Ratio 95% CI Never 1.0 ref. Former 1.4 0.6-2.9 Current 3.6 2.2-6.0 Based on the results table above, is the following statement true or false?Former smokers are significantly more likely than never smokers to experience a myocardial infarction.
False
A study was conducted to determine the rate of new back pain among undergraduate students during their first year of college. Only freshman students who started college without having ever experienced back pain were included in the study. Students were interviewed monthly throughout their first 12 months of college. At each interview, the students were asked if they have experienced back pain since the previous interview. Of the 200 student participants, 10 developed back pain during the study time frame, resulting in 10/200, or 5% per year. Does the result represent incidence or prevalence?
Incidence
Which answer is true regarding Pearson correlation (r)?
Is used when you have two continuous, normally distributed variables
A researcher is planning a study to determine the effect of a motivational interviewing approach on weight loss. The hypothesis is: motivational interviewing will decrease weight more than a handout regarding healthy eating (control group). Based on a priori specification of alpha = 0.05 and beta (i.e., power) of 0.80, the sample size calculation indicated that 100 subjects were needed in each group (i.e., 200 subjects total). The researcher randomly assigned 100 people to the treatment group and 100 people to the control group, measured each person's weight when they enrolled in the study, and measured each person's weight again at the end of the study. The average weight loss for participants in the treatment group was 5 pounds, and the average weight loos in the control group was 3 pounds (p=0.02). If the researcher wanted power of 0.95 (beta=0.05), what would happen to the required sample size? a. It would stay the same b. It would decrease c. It would increase
It would increase
Choose the correct statistical test for this analysis: The researcher is conducting data analysis to determine the significant predictors of college student smoking status (formatted as yes or no). Predictors you will analyze include: gender, history of smoking before college, smoking status of the parents, number of friends who smoke, works at least 10 hours per week, year in college, major in college. [Hint: ask yourself, is the outcome (dependent variable) dichotomous or continuous?]
Logistic Regression
Module 8, Lecture 1 explained the PEDro Scale for appraising research reports. Answer below based on Chuang, 2006. Appraisal Question 4: Were subjects, clinicians, and outcome assessors blinded? (HINT: you will have to watch the 2nd lecture or read the Methods section to answer this). Y/N?
No
The below table is adapted from: Beynnon et al. First-time inversion ankle ligament trauma. The American Journal of Sports Medicine 2005; 33 (10): 1485-1491. The table shows relative risk (95%CI) of an ankle ligament trauma among athletes by high school versus college athletes. Level Relative Risk (95% confidence interval) High School Reference group College 1.51 (0.79-2.86) Based on the above results, are college athletes at significantly higher risk of ankle ligament trauma as compared to high school athletes?
No
Choose the correct statistical test for this analysis: What is the effect of meditation on stress? 100 research participants will practice meditation daily for 2 months. Stress will be measured on a continuous scale, ranging from 0-100, before (PRE) and after (POST) the 2 month intervention. You will analyze the data to compare PRE vs POST stress values within each of the 100 subjects. Assume stress is a normally distributed variable.
Paired t-test
A study was conducted to determine how common back pain was among first year college students. Students were asked, "Are you currently experiencing back pain?" Of the 1,000 students who answered the question, 100 responded, "yes," resulting in a rate of 100/1000, or 10%. The researchers did not ask about their back pain history. Does the resulting rate of 10% represent incidence or prevalence ?
Prevalence
The research study reviewed in Module 8, Lecture 2 (Chuang, 2006) compared outcomes between cardiac rehab patients who performed treadmill training with virtual reality (VR group) to those who performed treadmill training without virtual reality (non-VR group). 12 subjects were randomized to each group. Both groups received cardiac rehab that consisted of 30 min treadmill training 2x/week for 3 months. Randomization was performed by having each subject draw a ball from a box (Ball A=non-VR, and Ball B=VR). Investigators were not involved in this randomization. During the study, 4 subjects were lost to follow up, resulting in 20 subjects completing the study. Refer to the Tables and Figures in Chuang to answer the question: What was the percent loss to follow up for each group?
The percent loss for each group was 2/12 = 17%.
The research study reviewed in Module 8, Lecture 2 (Chuang, 2006) compared outcomes between cardiac rehab patients who performed treadmill training with virtual reality (VR group) to those who performed treadmill training without virtual reality (non-VR group). 12 subjects were randomized to each group. Both groups received cardiac rehab that consisted of 30 min treadmill training 2x/week for 3 months. Randomization was performed by having each subject draw a ball from a box (Ball A=non-VR, and Ball B=VR). Investigators were not involved in this randomization. During the study, 4 subjects were lost to follow up, resulting in 20 subjects completing the study. Refer to the Tables and Figures in Chuang to answer the question: Is there evidence of differential loss to follow up?
There is not evidence of differential loss. Each group lost 2 subjects.
The research study reviewed in Module 8, Lecture 2 (Chuang, 2006) compared outcomes between cardiac rehab patients who performed treadmill training with virtual reality (VR group) to those who performed treadmill training without virtual reality (non-VR group). 12 subjects were randomized to each group. Both groups received cardiac rehab that consisted of 30 min treadmill training 2x/week for 3 months. Randomization was performed by having each subject draw a ball from a box (Ball A=non-VR, and Ball B=VR). Investigators were not involved in this randomization. During the study, 4 subjects were lost to follow up, resulting in 20 subjects completing the study. Refer to the Tables and Figures in Chuang to answer the question: Is the percent loss to follow up a possible limitation in drawing conclusions from the study results?
This is not at all a concern, because the loss to follow up was less than 15%.
The below table is adapted from: Beynnon et al. First-time inversion ankle ligament trauma. The American Journal of Sports Medicine 2005; 33 (10): 1485-1491. The table shows relative risk (95%CI) of an ankle ligament trauma among female athletes by sport. Sport Relative Risk (95% confidence interval) Soccer 1.14 (0.35-3.74) Field hockey 1.36 (0.45-4.08) Basketball 2.81 (1.02-7.76) Lacrosse Reference group Based on the above results, is the following statement True or False:Among female athletes who play soccer, field hockey, basketball or lacrosse, it is the basketball players who are at highest risk of an ankle ligament trauma, significantly higher than lacrosse players.
True
The below table is adapted from: Beynnon et al. First-time inversion ankle ligament trauma. The American Journal of Sports Medicine 2005; 33 (10): 1485-1491. The table shows relative risk (95%CI) of an ankle ligament trauma among male athletes by sport. Sport Relative Risk (95% confidence interval) Soccer 2.45 (0.74-8.14) Basketball 0.895 (0.16-4.97) Lacrosse Reference group Based on the above results, is the following statement True or False:Among male athletes, basketball players have a lower risk of an ankle ligament trauma as compared to lacrosse players, but this lower risk is not statistically significant.
True
The following table is adapted from: Njølstad I, Arnesen E, Lund-Larsen PG.Smoking, serum lipids, blood pressure, and sex differences in myocardial infarction. A 12-year follow-up of the Finnmark Study. Circulation. 1996 Feb 1;93(3):450-6. PubMed PMID: 8565161. The table shows Rate Ratios and 95% confidence intervals (CI) of myocardial infarction by smoking status. Smoking Status Risk of Myocardial Infarction Rate Ratio 95% CI Never 1.0 ref. Former 1.4 0.6-2.9 Current 3.6 2.2-6.0 Based on the results table above, is the following statement true or false?Current smokers are significantly more likely than never-smokers to experience a myocardial infarction.
True
The lectures present two types of regression analysis - linear regression and logistic regression. Linear regression analysis is used when the outcome is a continuous, normally distributed variable.
True
The lectures present two types of regression analysis - linear regression and logistic regression. True or False: Logistic regression is used when the dependent variable is dichotomous.
True
The lectures present two types of regression analysis - linear regression and logistic regression. True or False: Logistic regression results are considered statistically significant if the odds ratio confidence interval (CI) does not include 1.00.
True
T-test
X: 2 independent categories; Y: normally distributed continuous
ANOVA
X:>2 independent categories; Y: normally distributed continuous
Module 8, Lecture 1 explained the PEDro Scale for appraising research reports. Answer below based on Chuang, 2006. Appraisal Question 1: Did the investigators randomly assign (or allocate) subjects to groups? Y/N
Yes
Module 8, Lecture 1 explained the PEDro Scale for appraising research reports. Answer below based on Chuang, 2006. Appraisal Question 2: Was each subject's group assignment "concealed" from the persons enrolling? Y/N
Yes
Module 8, Lecture 1 explained the PEDro Scale for appraising research reports. Answer below based on Chuang, 2006. Appraisal Question 3: According to Table 2, did the groups have similar sociodemographic, clinical and prognostic characteristics at start? Y/N?
Yes
Module 8, Lecture 1 explained the PEDro Scale for appraising research reports. Answer below based on Chuang, 2006. Appraisal Question 5: Were all groups managed in the same way except for experimental intervention? Y/N
Yes
When designing an experimental/interventional research study, how can you control the placebo effect? a. By choosing a blind or double-blind study design b. By incentivizing subjects' participation c. By choosing a naturalistic setting d. By minimizing subject drop out
a. By choosing a blind or double-blind study design
Chi-square
a. Both X and Y are dichotomous variables
When designing an experimental research study, choosing a double-blind study design and using a control group will increase ____________ validity. a. Internal b. External
a. Internal
Identify the primary problem with the following survey question: "How satisfied are you with the variety of food items available in the cafeteria and with the price of the food items?" a. It is double-barreled b. It is loaded c. It is overly complex d. It is overly simple
a. It is double-barreled
The greater the variability (e.g. standard deviation) of the study outcome, the _____ sample size required a. Larger b. Smaller
a. Larger
The greater the variability (e.g. standard deviation) of the study outcome, the _____ sample size required. a. larger b. smaller
a. Larger
1. What is the most appropriate statistical test to answer the following research question: Is body weight significantly associated with minutes of exercise per day among UC students? Assume body weight data are normally distributed. a. Pearson correlation b. Student's t-test c. ANOVA d. Chi-Square
a. Pearson correlation
Module 8, Lecture 1 explained the PEDro Scale for appraising research reports. Answer below based on Chuang, 2006. Appraisal Question 6: How did the investigators analyze the data? a. Per protocol analysis b. Intention to treat analysis
a. Per Protocol
Analyzing the data using only subjects who complete the study according to the protocol is: a. Per protocol analysis b. Intention to treat analysis
a. Per protocol analysis
Review the PEDro scoring scale. Which study design will usually score a higher PEDro score? a. Randomized Controlled Trial b. Quasi-experimental study c. Observational study Qualitative study
a. Randomized Controlled Trial
The repeatability of measurements is related to: a. Reliability b. Validity
a. Reliability
A study where the results can be generalized to a population has a high degree of external validity. a. True b. False
a. True
The difference in weight loss between the treatment and control groups in Question 10 is statistically significant. a. True b. False
a. True
A study with a very high level of internal validity likely also has a very high level of external validity. a. True b. False
b. False
1. A study was done to determine if hearing loss (yes, no) is associated with age group (<50, 50-70, >70 years old) among older adults. What is an appropriate statistical test for this analysis? a. Linear regression b. Chi-square c. ANOVA
b. Chi-square
Analyzing the data using all subjects enrolled irrespective of whether they complete the study according to the protocol is: a. Per protocol analysis b. Intention to treat analysis
b. Intention to treat analysis
In a randomized controlled trial, analyzing the data using all subjects randomized, whether or not they finished the intervention, is termed: a. Per protocol analysis b. Intention to treat analysis
b. Intention to treat analysis
Using imputation to extrapolate missing data for persons who were lost to follow up is part of: a. Per protocol analysis b. Intention to treat analysis
b. Intention to treat analysis
The correlation between measurements from multiple observers observing the same participant at the same event is used to establish ______________. a. Test-retest reliability b. Inter-rater reliability* c. Internal consistency reliability d. Construct reliability
b. Inter-rater reliability
_____________ is an example of non-probability sampling, while _____________ is an example of probability sampling. a. Stratified random sampling, purposive sampling b. Purposive sampling, stratified random sampling c. Cluster random sampling, snowball sampling d. Homogenous sampling, purposive sampling
b. Purposive sampling, stratified random sampling
_______________ refers to the reproducibility (consistency) of the measurements method, while ________________ is indicative of your method actually measuring the attribute that you intend to measure. a. Validity, reliability b. Reliability, validity c. Dependability, stability Stability, dependability
b. Reliability, validity
A research study investigating subject satisfaction with weight loss programs suggested a benchmark loss of at least 7 pounds is needed for a person to be "satisfied" with their weight loss. Using this benchmark and the study results described in Question 10, what is your interpretation? a. The weight loss difference between the treatment and control groups (2 pounds) is statistically significant and therefore clinically meaningful. b. The weight loss difference between the treatment and control groups (2 pounds), although statistically significant, may not be clinically meaningful. c. The weight loss difference between the treatment and control groups (2 pounds) is neither statistically significant nor clinically meaningful.
b. The weight loss difference between the treatment and control groups (2 pounds), although statistically significant, may not be clinically meaningful.
A researcher is planning a study to determine the effect of a motivational interviewing approach on weight loss The hypothesis is: motivational interviewing will decrease weight more than a handout regarding healthy eating (control group). The researcher randomly assigned 100 people to the treatment group and 100 people to the control group, measured each person's weight when they enrolled in the study, and measured each person's weight again at the end of the study. The average weight loss for participants in the treatment group was 5 pounds, and the average in the controls group was 3 pounds (p=0.02). A different research study investigating subject satisfaction with weight loss programs suggested a benchmark loss of at least 7 pounds is needed for a person to be "satisfied" with their weight loss. Synthesizing information from both the benchmark study and the above randomized controlled trial, what is your conclusion regarding the randomized controlled trial results? a. The difference in weight loss between the treatment and control groups is statistically significant and therefore clinically meaningful. b. The weight loss difference between the treatment and control groups, although statistically significant, may not be clinically meaningful. c. The weight loss difference between the treatment and control groups, although statistically significant, may not be clinically meaningful.
b. The weight loss difference between the treatment and control groups, although statistically significant, may not be clinically meaningful.
Chuang et al (2006) compared outcomes between cardiac rehab patients who performed treadmill training with virtual reality (VR group) versus those who performed treadmill training without virtual reality (non-VR group). 24 subjects were randomized to one of two groups: 1) VR group (n=12), or 2) non-VR group (n=12). Study design was a randomized control trial. All subjects received cardiac rehab (including 30 min of treadmill training) 2x/week for 3 months. During the study, 4 subjects were lost to follow up, resulting in 20 subjects completing the study. Each group lost 2 subjects. Choose the best answer below. a. You are concerned about differential loss to follow up b. You are slightly concerned about the percent loss to follow up, because it is a little over 15%
b. You are slightly concerned about the percent loss to follow up, because it is a little over 15%
A study was done to compare the effects of 8 weeks of meditation versus 8 weeks of aerobic exercise on reducing stress in college students. 20 students were randomized to either 1) meditation or 2) exercise. The null hypothesis was: there will be no difference in stress between the groups after 8 weeks of treatment. The published article didn't have a sample size calculation in the Methods section. The results showed no difference in stress between the groups after 8 weeks of treatment. As a critical reviewer of the scientific literature, what are your thoughts regarding this study? a. You believe the results are valid because the study was a randomized control trial and that is the strongest study design for showing a "cause -effect" relationship. b. You are suspicious of a Type II error (accepting the null hypothesis falsely).
b. You are suspicious of a Type II error (accepting the null hypothesis falsely).
1. What is the most appropriate statistical test to answer the following research question: Does body weight differ between freshman, sophomore, junior, and senior students at UC? Assume body weight data are normally distributed. (more than 2 categories) a. Pearson correlation b. Student's t-test c. ANOVA d. Chi-Square
c. ANOVA
Comparing a new measure to the current gold standard is used to establish what type of validity? a. Face validity b. Construct validity c. Concurrent validity d. Divergent validity
c. Concurrent validity
The type of reliability assessed using the statistic Cronbach's alpha is: a. Test-retest reliability b. Interrater reliability c. Internal consistency reliability d. Construct reliability
c. Internal consistency reliability
Choose the best answer below regarding the PEDro scale. a. Total score ranges from 0-11 b. A score of 0 suggests there are no problems with the study and it appraises well c. Is typically used for randomized control trials
c. Is typically used for randomized control trials
A researcher is planning a study to determine the effect of a motivational interviewing approach on weight loss. The hypothesis is that the treatment group (motivational interviewing) will decrease their weight more than a control group (handout regarding healthy eating). Based on a priori specification of alpha = 0.05 and beta of 0.20 (i.e., power of 0.80), the sample size calculation indicated that 100 subjects were needed in each group (i.e., 200 subjects total). The researcher randomly assigned 100 people to each group, measured each person's weight when they enrolled in the study, and measured each person's weight again at the end of the study. The average weight loss in the treatment group was 5 pounds, and the average weight loss in the control group was 3 pounds (p=0.02). If the researcher wanted power of 0.95 (beta=0.05), how would this change the sample size calculation result? a. It would stay the same b. It would decrease c. It would increase
c. It would increase
1. Standardized effect sizes of >0.70 are considered: a. Minimal b. Moderate c. Large
c. Large
The above study (in question 10) is an example of what kind of design? Based on a priori specification of alpha = 0.05 and beta of 0.20 (i.e., power of 0.80), the sample size calculation indicated that 100 subjects were needed in each group (i.e., 200 subjects total). The researcher randomly assigned 100 people to each group, measured each person's weight when they enrolled in the study, and measured each person's weight again at the end of the study. The average weight loss in the treatment group was 5 pounds, and the average weight loss in the control group was 3 pounds (p=0.02). If the researcher wanted power of 0.95 (beta=0.05), how would this change the sample size calculation result? a. Prospective cohort b. Cross-sectional c. RCT d. Retrospective case-control
c. Randomized Controlled Trial
The individuals selected to participate in a research study are called the__________. a. Target population b. Accessible population c. Sample
c. Sample
Having an adequate sample size in a study is important to be able to statistically test a hypothesis. Choose the best answer regarding sample size. a. Having a small sample size (not enough subjects) may result in a Type I error b. The sample size justification (e.g. calculation) is usually found in the Methods section c. Sample size needed for a study is dependent on several factors including effect size expected and the variability (e.g. standard deviation) of the outcome d. b and c above e. all of the above
c. Sample size needed for a study is dependent on several factors including effect size expected and the variability (e.g., standard deviation) of the outcome
Having an adequate sample size in a study is important for being able to statistically test a hypothesis. Choose the best answer regarding sample size. a. Having a too small sample size may result in a Type I error. b. The sample size justification (e.g. calculation) may be found in the Results section. c.The hypothesized effect size and variability (e.g. standard deviation) of the outcome are both important factors to consider in determining the study sample size.
c. The hypothesized effect size and variability (e.g. standard deviation) of the outcome are both important factors to consider in determining the study sample size.
A study was done to compare the effects of 8 weeks of meditation versus 8 weeks of aerobic exercise on stress in college students. 20 students were randomized to either: meditation exercise The null hypothesis was: There will be no difference in stress between the groups after 8 weeks of treatment. The published article didn't have a sample size calculation in the Methods section. The results showed no difference in stress between the groups after 8 weeks of treatment. What is your conclusion regarding this study? a. You believe the conclusion to be valid because it was a randomized control trial and that is the strongest study design to show "cause -effect" relationship b. You are suspicious of a Type II error (accepting the null hypothesis falsely) c. You are suspicious of not enough power due to small sample size d. b and c above
c. You are suspicious of not enough power due to small sample size
The statistical test (type of analysis) you would use to analyze the association between two dichotomous variables is...
chi-square
The statistic test (type of analysis) you would use to examine the association between two continuous variables is... Group of answer choices
correlation
What is the best statistical test to use to answer the following research question: "is body weight significantly associated with minutes of exercise per day among UC students?" under the assumption that data is normally distributed.
correlation
In the study presented in the previous question (in question 8), the article did not include a sample size calculation in the Methods section. Which section of the article would you most likely find the authors mention the possibility of the study being limited by a small sample size? a. Background/Introduction b. Methods c. Results d. Discussion
d. Discussion
1. Which answer is true regarding the Pearson correlation coefficient (r)? a. Ranges from 0 (no correlation) to 1 (strong correlation) b. Relates strength but not direction c. Infers "causation" (i.e. cause-effect relationship) d. Is used when you have 2 normally distributed continuous variables
d. Is used when you have 2 normally distributed continuous variables
The ankle anterior drawer test has a good validity when compared to MRI in diagnosing ankle ligament sprain. What type of validity does this statement represent? A. Face validity B. Expert validity C. Construct validity D. Criterion validity - predictive validity E. Criterion validity - concurrent validity
e. Criterion validity - concurrent validity
Researchers can reduce threats to internal validity by using _____________. a. randomization to form equivalent groups with minimum of systemic bias b. a control group c. a single blind or double-blind study design d. appropriate instruments and calibrating equipment e. all of the above can be used to reduce threats to internal validity
e. all of the answers can be used to reduce threats to internal validity
Results report the beta coefficient
linear regression
The beta coefficient can range from -infinity to +infinity- linear regression
linear regression
The standardized beta coefficient is expressed in terms of SD units
linear regression
Used when the dependent variable is continuous
linear regression
Results report the odds ratio (OR)
logistic regression
The confidence interval can range from 0.0 to infinity
logistic regression
The result is not significant if the confidence interval (CI) crosses 1
logistic regression
Used when the dependent variable is dichotomous
logistic regression