IA2 Flashcards
What are the similarities between a t-distribution and a Normal distribution?
Both are symmetric and unimodal.
What are the 4 conditions for a binomial distribution?
Binary (success/failure) Independent Number of trials is fixed Same success (probability of success is the same)
When are results statistically significant?
When the p-value is greater than alpha, or 0.05, if no significance level is set by the problem.
What is the relationship between the standard deviation of a population and the mean of the sampling distribution of x-bar?
The standard deviation of the sampling distribution of x-bar will always be smaller.
How do you find degrees of freedom?
df = n-1
What is a t-distribution?
The t distribution distribution that is used to estimate population parameters when population variance/standard deviation is unknown (when we use the sample variance/standard deviation instead)
What conditions must be checked in order to show that the sampling distribution of x-bar is approximately Normal?
The sample size must be greater than 30 or the population must be Normally distributed.
What is the relationship between the mean of a population and the mean of the sampling distribution of x-bar?
They are the same.
What happens to the width of a confidence interval when you increase the sample size?
The confidence interval becomes narrower.
What does it mean for test results to be statistically significant?
Statistically significant means that the results were not likely to happen by chance.
What is the name of the procedure we use to construct a confidence interval for the population mean?
One sample t interval for miu
What happens to the width of a confidence interval when you increase the confidence level?
The confidence interval becomes wider.
What is expected value referring to?
The mean of a random variable.
What are the three conditions required to construct a confidence interval for p?
Random, 10%, Normal
How do you check for Normality when constructing a confidence interval for miu?
The sample size must be greater than 30 or the population must be Normally distributed.
What conditions must be checked in order to calculate the standard deviation of the sampling distribution of x-bar?
10% condition
What happens to the width of a confidence interval when you decrease the confidence level?
The confidence interval becomes narrower.
What makes a t-distribution different from a Normal distribution?
The t-distribution has more variability than a Normal distribution. It has more area in the tails.
How do you check for Normality when constructing a confidence interval for p?
n*p-hat is greater than or equal to 10 n(1-p-hat) is greater than or equal to 10
What is the margin of error?
The margin of error is the maximum expected difference between the statistic and the parameter.
What happens to the width of a confidence interval when you decrease the sample size?
The confidence interval becomes wider.
What is the name of the procedure we use to construct a confidence interval for the population proportion?
One sample z interval for p.
What are the three conditions required to construct a confidence interval for miu?
Random, independent, Normal
How do degrees of freedom/sample size impact the shape of a t-distribution?
As the sample size/degrees of freedom increase, the t-distribution get closer to a Normal distribution.
