Vocab II Flashcards
confidence interval
is another type of estimate, but its not just one number but its an interval of numbers. will likely include the unknown population parameter
interval of numbers
is a range of values calculated from a given set of sample data
what is your level of confidence in decimal form?
the percentage of area in the body of our bell curve
what is your alpha?
1 - confidence level = alpha
alpha is the total area of both tails
p^1, Po, p̂, p-hat
sample proportion
unknown σ or small n(size/sample size)
if we do not know σ or if we have a sample size less than 30, we need to use the t-distribution instead of Z.
how is t found
t-table
n- 1 = df
when do we use z-score/population standard deviation?
when it states its a population sample or the sample size is 30 or more!
when do we use t-score/sample standard deviation?
when it states its a sample standard deviation or the sample size is less than 30!
hypothesis testing
the most important statistical test. involves collecting data from a sample and evaluating it. this is how a decision is made using the evidence
null hypothesis
Ho:
if it is a statement of no difference between the variables- they are not related. this can be considered the status quo
alternative hypothesis
Ha:
it is a claim about the population that is contradicting to Ho and what we conclude when we cannot accept Ho. This is usually what the researcher is trying to prove
how are decisions made through Ho: and Ha:
by examining the evidence to decide if there is enough evidence to reject the null hypothesis of not
what are the two decisions?
reject H:o or do not reject H:o
you will never states a decision based on Ho
How is Ho: worded?
Ho: will have an equal sign in it while
equal to =
greater than or equal to ≥
less than or equal to ≤
how is Ha: worded?
Ha: will not have an equal sign
not equal ≠
greater than >
less than <
Key words for Ho: when it is =
equals
is the same as
key words for Ha: when it is ≠
not equal
differs
not the same as
is different than
key words for Ho: when it is ≥
greater than or equal to
is at least
key words for Ha: when it is <
less than
fewer than
smaller than
key words for Ho: when it is ≤
less than or equal to
is at most
key words for Ha: when it is >
greater than
more than
bigger than
how to write out a test statistic
- set up the Ho and Ha
- draw a picture (is it one tailed or two tailed)
- find the level of significance and critical value
- find the test statistic
- is it in the tail?(reject null) is it not in the tail?(fail to reject null)
type II error
occurs when you don’t reject the null hypothesis when it was false
type I error
occurs when you reject a good null hypothesis when it was true
what is a sampling distribution
is a probability distribution of a statistic that is obtained through repeated sampling of a specific population
central limit theorem
is how we are able to make conclusions about a population, even if we do not know the true mean
sampling distribution vs. population distribution
the sampling distribution will be a normal distribution(population) if we have a large enough sample size (more than 30)
is the mean of the sampling distribution ever going to be exactly the mean of the population?
NO
