39 Questions
What type of statistical test would you use to compare two means if the design was related?
Dependent t test
When comparing two separate groups that do not meet the criteria for a parametric test, which non-parametric test should be used?
Mann Whitney test
For investigating an association between two continuous variables, which statistical test should be used?
Persons r
What factor should be considered when choosing a statistical test?
Type of question and nature of the data
Which statistical test would you use for investigating an association between category data?
Chi square test
What is the purpose of significance testing in statistics?
To determine the probability of random occurrences
What is the role of a hypothesis in statistical testing?
To predict the average expected outcome from a single investigation
What is the primary function of inferential statistics?
To test hypotheses and make inferences about a population
When is a hypothesis considered testable?
When it predicts the average expected outcome from a single investigation
What does comparing means help to determine in statistics?
Statistical differences between groups
What type of test did the authors choose to compare the BMI between groups at baseline?
Independent t test
Based on the given information, what is the null hypothesis (H0) for the chosen test?
There is no significant difference in BMI between the groups at baseline.
What statistical test would be the non-parametric equivalent of the independent t test?
Mann-Whitney test
What do the authors use to determine if the data is normally distributed?
Histograms and Shapiro-Wilk tests
What does the Levene's Test for Equality of Variances indicate in this context?
Whether the groups have equal variances
When should a two-tailed test be used?
When the intervention's effect can go in either direction
What is the null hypothesis (Ho) for the one-tailed test regarding physical performance?
The intervention will not affect physical performance
Why is a larger sample size required when considering the chances of negative effects from an intervention?
To measure the intervention's chances of causing negative effects more precisely
What is traditionally considered statistically significant when testing a hypothesis using a p-value?
Probability less than 5%
What does the test statistic take into account when testing a hypothesis?
Difference in means for two sample groups and standard error
What does a p-value of less than 0.05 indicate?
The results are statistically significant and the null hypothesis can be rejected
What does the negative association between age and SPPBA_TOTAL indicate?
There is a negative relationship between age and SPPBA_TOTAL
What is the purpose of applying an inferential statistical test?
To test a hypothesis and determine the probability of findings being due to chance
What type of data is Spearman’s Rho Correlation suitable for?
Ordinal or scale data that is not normally distributed
What should be the significance level for a correlation coefficient to be considered significant?
$p<0.05$
In the context of simple associations, which term is used for exploring how the change in one variable is associated with change in another variable?
Bivariate relationships
Which type of statistical test is suitable for comparing two continuous variables, such as studying time and grades?
Pearson correlation
What is the appropriate statistical test for comparing the fitness levels of dog owners vs. non-dog owners?
Independent t-test
Which statistical test is suitable for comparing the relationship between categorical and dichotomous variables, such as Irish office workers and the presence of heart disease?
Chi-square test
What descriptive statistics should be presented if the data is skewed?
Median and interquartile range
In controlled trials, why is it important to present summary statistics at baseline?
To allow comparison of outcomes between groups
Where are descriptive statistics traditionally reported in controlled trials?
Table 1
What type of data should be plotted in histograms and boxplots for inferential statistical analysis?
Continuous data
Which test should be used for testing normality with less than 2,000 observations?
Shapiro-Wilk test
What is the purpose of reporting inferential data in Table 2?
To present statistical tests for differences
Why is it important to know whether the data is categorical or continuous for inferential statistical analysis?
To decide on the appropriate statistical tests
In controlled trials, what does comparing outcomes between groups at baseline help to ensure?
Comparability of the groups at the start of the trial
Where should you report that you tested the data for normality?
Methods section under 'data analysis'
Which test should be used for testing normality with more than 2,000 observations?
Kolmogorov-Smirnov test
Study Notes
Statistical Tests for Comparing Means
- A paired t-test is used to compare two means if the design is related
- A Wilcoxon signed-rank test is a non-parametric test used when comparing two separate groups that do not meet the criteria for a parametric test
Investigating Associations
- A Pearson correlation coefficient is used to investigate an association between two continuous variables
- A chi-squared test is used to investigate an association between category data
Choosing a Statistical Test
- A key factor to consider when choosing a statistical test is the type of data and the research question
Hypothesis and Significance Testing
- The purpose of significance testing is to determine whether the results of a study are due to chance or a real effect
- A hypothesis is a statement that can be tested through experimentation or data collection
- A hypothesis is considered testable if it can be supported or rejected based on data
- The primary function of inferential statistics is to make inferences about a population based on a sample
Comparing Means and Hypothesis Testing
- Comparing means helps to determine whether there is a significant difference between two groups
- The null hypothesis (H0) states that there is no significant difference between the two groups
- A two-tailed test is used when the direction of the effect is unknown
Normality and Distribution
- Levene's Test for Equality of Variances indicates whether the variance of the data is equal across different groups
- A non-parametric test, such as the Wilcoxon rank-sum test, is used when the data is not normally distributed
- A larger sample size is required when considering the chances of negative effects from an intervention
Statistical Significance and P-values
- A p-value of less than 0.05 indicates that the results are statistically significant
- The test statistic takes into account the sample size and the observed effect size
- A p-value indicates the probability of obtaining the observed results by chance
Correlation and Regression
- Spearman's Rho correlation is suitable for ordinal data
- A correlation coefficient is considered significant when the p-value is less than 0.05
- The purpose of applying an inferential statistical test is to make inferences about the population based on the sample data
Data Types and Statistical Tests
- Continuous data is suitable for parametric tests, such as t-tests and ANOVA
- Categorical data is suitable for non-parametric tests, such as chi-squared tests and Fisher's exact test
Presenting Statistics in Controlled Trials
- Descriptive statistics should be presented for skewed data
- Summary statistics should be presented at baseline in controlled trials to ensure that the groups are comparable
- Inferential data is traditionally reported in tables and figures
This quiz covers the concepts of one-tailed and two-tailed hypotheses in research. It discusses the considerations when choosing between one-tailed and two-tailed tests, with examples of how these hypotheses are formulated and applied in experimental settings.
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