Unit 6 A Flashcards
(25 cards)
What is the purpose of hypothesis testing in statistics?
To determine whether there is enough evidence to reject a null hypothesis.
True or False: The null hypothesis is usually a statement of no effect or no difference.
True
What is a p-value?
The probability of obtaining a test statistic at least as extreme as the one observed, assuming the null hypothesis is true.
Fill in the blank: A __________ error occurs when the null hypothesis is rejected when it is actually true.
Type I
What is the significance level (alpha) in hypothesis testing?
The threshold for rejecting the null hypothesis, commonly set at 0.05.
Define Type II error.
Failing to reject the null hypothesis when it is actually false.
What does a confidence interval represent?
A range of values that is likely to contain the population parameter with a certain level of confidence.
True or False: A 95% confidence interval means that 95% of the data points fall within that interval.
False
What is the difference between one-tailed and two-tailed tests?
One-tailed tests evaluate the direction of an effect, while two-tailed tests evaluate both directions.
In hypothesis testing, what is the role of the test statistic?
It is used to determine how far the sample statistic is from the null hypothesis.
What is the meaning of ‘power’ in hypothesis testing?
The probability of correctly rejecting a false null hypothesis.
Fill in the blank: The __________ is the distribution of the sample means.
sampling distribution
What is the Central Limit Theorem?
It states that the sampling distribution of the sample mean approaches a normal distribution as the sample size increases.
True or False: The standard error decreases as the sample size increases.
True
What is an alternative hypothesis?
The hypothesis that indicates the presence of an effect or difference.
What is the formula for calculating the z-score?
z = (X - μ) / σ
What does it mean if a result is statistically significant?
It indicates that the observed effect is unlikely to have occurred by chance.
Fill in the blank: The __________ test is used to compare the means of two independent groups.
t-test
What is the main assumption of the t-test?
The data should be approximately normally distributed.
What does it mean to ‘fail to reject the null hypothesis’?
There is not enough evidence to support the alternative hypothesis.
What is a critical value?
A threshold that determines the cutoff for rejecting the null hypothesis.
True or False: A larger sample size increases the power of a statistical test.
True
What is the difference between a parameter and a statistic?
A parameter is a characteristic of a population, while a statistic is a characteristic of a sample.
What is a t-distribution?
A probability distribution used for hypothesis testing when the sample size is small and the population standard deviation is unknown.
