Independent vs Dependent Samples
This type of sample involves measuring the same individuals at multiple time points.
What are dependent samples?)
This test is used to compare means between two independent groups.
What is an independent t-test?
This type of test assumes data follows a normal distribution.
What are parametric tests?
This level of measurement has categories with no inherent order.
What is nominal?
A researcher uses an independent t-test to compare pre-test and post-test scores in the same students. What's wrong?
Should use paired t-test - these are dependent samples
A study comparing blood glucose levels between diabetic and non-diabetic patients involves this type of sample.
What are independent samples?
This test compares proportions across multiple groups.
What is chi-square test?
This advantage of parametric tests means they're less likely to make a Type II error.
What is statistical power?
Patient satisfaction rated as 1=poor, 2=fair, 3=good, 4=excellent represents this level.
What is ordinal?
A study with 20 patients per group showing heavy skew uses a parametric t-test. What's the issue?
Should use non-parametric Mann-Whitney U due to non-normal distribution and small sample
Comparing twin siblings' birth weights would involve this type of sample.
What are dependent samples?
This test examines whether a continuous outcome can be predicted by multiple predictor variables.
What is multiple linear regression?
A z-score exceeding this absolute value typically indicates an outlier.
What is 3?
This level of measurement has equal intervals and a true zero point.
What is ratio?
A researcher uses Pearson correlation on ordinal data with only 4 levels. What's the problem?
Should use Spearman's rank correlation for ordinal data
Violating the independence assumption by treating dependent samples as independent leads to incorrect versions of these two statistical values.
What are p-values and confidence intervals?
This is the non-parametric alternative to a paired t-test.
What is Wilcoxon signed-rank test?
This is the non-parametric equivalent of Pearson correlation.
What is Spearman's rank correlation?
For a dependent variable at this level of measurement, you would typically use chi-square or logistic regression.
What is categorical/nominal?
A study compares depression scores across 4 treatment groups using multiple independent t-tests. What's wrong and what should be used?
Inflates Type I error; should use ANOVA
A study compares pre-surgery anxiety, post-surgery anxiety, and anxiety at 1-month follow-up in the same patients. This study involves this many repeated measures.
What is three repeated measures?
You want to test if meditation reduces stress in 40 nurses measured at 4 time points over 6 months, with normally distributed continuous data. Name the test.
What is repeated measures ANOVA?
Name two assumptions that parametric tests make about data.
What are normality, homogeneity of variances, and interval/ratio data? - accept any two)
Temperature in Celsius is this level of measurement because zero doesn't mean 'absence of temperature.
What is interval?
A researcher interprets a regression coefficient without controlling for confounders and claims causation. Name two problems.
What are: not controlling for confounding leading to spurious relationships, and correlation/prediction doesn't equal causation?