Class 8, 9 Spring α―α‘£π© Flashcards
What is joint probability?
The probability of getting the variables/processes/outcomes A or B
βOrβ means and/or.
What is the probability for independent variables A and B?
The probability for events from independent variables/processes/outcomes A and B.
What is the probability for dependent variables A and B?
The probability of outcome A, given knowledge about B.
What percentage of people like In-N-Out best?
68% of people like In-N-Out best.
What is the percentage of women who prefer In-N-Out?
72% of women prefer In-N-Out.
What is the percentage of men who prefer In-N-Out?
65% of men prefer In-N-Out.
What are descriptive statistics?
Methods used to summarize or describe observations in a particular sample.
What are inferential statistics?
Using observations as a basis for making estimates or predictions about a situation that has not yet been observed.
Give an example of descriptive statistics.
Calculating the average height of a whole classroom.
Give an example of inferential statistics.
Extrapolating the average height of one 5th grade class to predict another.
What is a population in statistics?
All the cases or situations that the statistician wants their inferences to apply to.
What is a sample?
A relatively small selection from within a population.
What is a simple random sample?
An approach where each element of the population is likely to be selected.
What does inferential statistics focus on?
Making estimates and inferences about a wider population.
What is random error?
Describes how much an estimate will tend to vary from one sample to the next.
What is the symbol for sample size?
n.
What is the symbol for population size?
N.
True or False: Random error has a preferred direction away from the mean.
False.
What is systematic bias?
The difference between survey results and population values due to incorrect measurements.
What can cause measurement bias?
Incorrect measurements from broken tools or poorly trained assistants.
What can cause sampling bias?
Not selecting a truly random sample representative of the larger population.
What is the impact of random error on estimates?
It may be imprecise, but not inaccurate.
What is the main way to reduce random error?
Collecting more data (increasing sample size).
What is the paradox of sampling?
A sample is misleading unless it is representative of all natural variation in a population.
What is a confidence interval?
A range of plausible values where we are likely to find the true population parameter.
What conditions must be checked for constructing a confidence interval?
The sampling distribution must be normally distributed and unbiased.
What is the central limit theorem?
A theorem that describes the conditions under which the sampling distribution of the sample mean will be normally distributed.
What is a confidence interval (CI)?
A range of plausible values where we are likely to find the population parameter
A confidence interval represents uncertainty in estimates and accounts for random errors.
What is the purpose of using confidence intervals?
To provide a plausible range of values for the population proportion instead of just a point estimate
This helps capture the true parameter more effectively.
What does the sample proportion p-hat represent?
A single plausible value for the population proportion p
p-hat is derived from sample data and is subject to error.
Why is using only a point estimate compared to fishing in a murky lake with a spear?
Because it has a high chance of missing the true population parameter
A point estimate does not account for variability or uncertainty.
What is the analogy used to describe confidence intervals?
Fishing with a net
A net increases the chances of capturing fish, similar to how a CI increases the likelihood of capturing the true parameter.
What must be ensured for a confidence interval to be constructed?
The sampling distribution must be normally distributed and unbiased
This is related to the conditions of the central limit theorem.
What is the relationship between standard error and sample proportion?
The sample proportion has some standard error associated with it
Standard error quantifies the variability of the sample proportion as an estimate of the population proportion.
Fill in the blank: A confidence interval is like fishing with a net, representing a range of _______.
[plausible values]
This analogy emphasizes the idea of capturing a range of potential outcomes.
What theoremβs conditions need to be checked for confidence intervals?
Central Limit Theorem
This theorem ensures that the sampling distribution approaches normality as sample size increases.
