ex 2 inference for one p notes

Question 1

trial

Answer 1

-a single event that leads to an outcome
-every guess or turn taken
-has two possible outcomes, success or failure

Question 2

sample proportion of a trial

Answer 2

phat = #of successes/#of trials

Question 3

sampling distribution

Answer 3

the distribution of all possible values for the sample statistic
- we generate a sampling distribution that resembles the normal distribution by repeatedly taking samples of the same size from a population and calculating the sample proportion (phat)
- gives us an idea of the values that the sample statistic take

Question 4

when is the sampling distribution for phat nearly normal?

Answer 4

when two conditions are met:
independence
success-failure

Question 5

independence

Answer 5

sample observations are independent of one another
- value of any one observation has no impact on the value of any other observation in the data
“random sample”

Question 6

success-failure check

Answer 6

there are at least 10 successes and 10 failures
when the amount of successes/failures aren’t given, use the equation on formula sheet

Question 7

standard error

Answer 7

standard deviation for sampling distribution that is nearly normal with mean p
SE= sqrt Po(1-po)/n

Question 8

difference between standard deviation and standard error

Answer 8

standard deviation is the variability in data or in populations
standard error is the standard deviation of an estimate

standard deviation refers to data
standard error refers to an estimate

Question 9

test statistic

Answer 9

z-value
tells us how our sample statistic(phat) compares to the hypothesized value Po, using the standard error as out yardstick

z = (phat-Po)/sqrtPo(1-Po)/n

Question 10

confidence intervals

Answer 10

point estimate +- margin of error

phat +- multiplier*sqrt(phat(1-phat))/n

Question 11

multiplier

Answer 11

depends on how confident we want to be in our interval

Question 12

confidence level

Answer 12

tells us how sure we are that the confidence interval we constructed contains the parameter we are estimating

Question 13

critical values

Answer 13

z*
there are z* multiplier values you can use to find the confidence interval of a population proportion, depending on how confident we want to be with the interval