Statistics Revision: Lecture 1-2, Null Hypothesis

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What is the primary purpose of the null hypothesis in a research study?

To provide an estimate of the population variance

To calculate the sample size required for a study

To prove that there is a real effect or relationship in the population

is a statement that there is no effect or no difference between two variables or groups. It is the default or starting position that researchers aim to disprove through their study. (correct)

Which of the following statements is true about the null hypothesis?

It is usually stated as an inequality

It is a statement that there is no effect or no difference between two variables or groups (correct)

It represents the idea that there is a real effect or relationship in the population

It is used to calculate the sample variance

What is the alternative hypothesis (H1 or Ha) in a research study?

A statement that there is no effect or no difference between two variables or groups

A measure of the spread or dispersion of values within a dataset

A type of statistical analysis used to compare means

A statement that there is an effect or relationship in the population (correct)

What is the main difference between sample variance and population variance?

Sample variance is a measure of the spread or dispersion of values within a sample, while population variance is a measure of the spread or dispersion of values within a population Signup and view all the answers

Why do researchers use statistical methods in psychology?

To quantify the spread or dispersion of values within a dataset and make informed conclusions Signup and view all the answers

What is the primary reason why researchers reject the null hypothesis?

Because there is sufficient evidence to conclude there is a real effect or relationship in the population Signup and view all the answers

What is the purpose of significance testing?

To provide probabilistic information and corroborate theories Signup and view all the answers

What happens to the sampling distribution of the mean as the sample size increases?

It approaches a normal distribution Signup and view all the answers

What does a small p-value indicate?

The null hypothesis should be rejected Signup and view all the answers

What is the purpose of the null hypothesis in significance testing?

To state there is no effect or difference Signup and view all the answers

What is the relationship between the standard deviation of the sampling distribution and the sample size?

The standard deviation decreases as the sample size increases Signup and view all the answers

What is the primary role of the p-value in significance testing?

To measure the probability of the observed result Signup and view all the answers

What does a larger p-value (greater than 0.05) indicate about the observed data?

That the observed data is reasonably likely to have occurred even if the null hypothesis is true Signup and view all the answers

According to Gelman (2016), why is the replication crisis more prominent in psychology?

Because psychology focuses on the concepts of validity and reliability Signup and view all the answers

What is a common route to replication issues in research?

P-hacking and data dredging Signup and view all the answers

What is a consequence of psychology's focus on validity and reliability?

Psychology is more open to criticism Signup and view all the answers

Why is the replication crisis more prominent in psychology, according to Gelman (2016)?

Because psychology is a more open field Signup and view all the answers

What is a result of overconfidence in research designs?

An increase in the likelihood of replication issues Signup and view all the answers

What is a key assumption about the distribution of population errors in statistical models?

They are normally distributed Signup and view all the answers

What is the main difference between a discrete variable and a continuous variable?

Discrete variables have specific values, while continuous variables can take any value Signup and view all the answers

What is the primary goal of model building in statistical analysis?

To fit the model to the actual data Signup and view all the answers

Why is it important to check descriptive statistics for signs of miscoding or other mistakes?

To detect errors in the data collection process Signup and view all the answers

What is the primary difference between process models and statistical models?

Process models are theoretical, while statistical models are empirical Signup and view all the answers

What is the typical structure of data in statistical analysis?

Matrices with rows as respondents and columns as variables Signup and view all the answers

What can occur when researchers make a series of decisions during data analysis without pre-specifying an analysis plan?

An increase in the false-positive rate Signup and view all the answers

What is the purpose of preregistering hypotheses in a research study?

To decrease the false-positive rate Signup and view all the answers

What is the formula for a (1−α) × 100% Confidence Interval for the population mean μ when the population standard deviation σ is known?

$$M \pm z_{\frac{\alpha}{2}}\frac{\sigma}{\sqrt{n}}$$ Signup and view all the answers

What is the term for the population standard deviation σ divided by the square root of the sample size n?

Standard error of the mean Signup and view all the answers

What is the value of α in the context of a 95% Confidence Interval?

0.05 Signup and view all the answers

What is the purpose of using a Confidence Interval for the population mean μ?

To provide a range of values within which the population mean μ is likely to lie Signup and view all the answers