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What is a parameter?
A number that describes some characteristic of the population
What is a statistic?
A number that describes some characteristic of a sample.
What is a sampling distribution? (test question)
The distribution of values taken by similar samples from the same population and a statistic is recorded.
As sample size increases ____ decreases
variability
The higher the sample size, the closer you are to the __________ mean
true population
What is an unbiased estimator?
When characteristics of the sampling distribution nearly resemble ones in a parameter (EX: mean)
What is an example of a biased estimator?
range
Recall the target table (2 by 2) with high accuracy, high precision, etc. Draw a picture of that.
What do the targets represent?
Accurate = Unbiased (in the center)
Precise = Low variability (clustered together)
High Accuracy Low Accuracy
High
Precision close to target far from the target
clustered together clustered together
Low
Precision close to target far from target
not clustered not clustered
What is ^
p
Probability from a SAMPLE proportion
What is p?
Population probability
What is the mean of a sample distribution?
M = P It is equal to the population probability
p
What are the categorical symbols for a parameter and sample? (categorical)
P and ^
P
What are the quantitative symbols for a parameter and sample?
M and -
x
When finding the standard deviation, you first have to do what?
Check the 10% condition!!!!!!
When finding mean, you first have to do what?
See if it was random through random selection or assignment.
When seeing if a sampling distribution is approximately normal, you first have to do what?
Check the large counts condition
What is the large counts condition?
When np>10 and n(1-P)>10
- -
To find the shape of a sample distribution what do you need to do first?
Check the Large Counts Condition
To find the center of a sample distribution what do you need to do first?
Check if the variable is random through random assignment or random selection
To find the spread of a sample distribution what do you need to do first?
Check 10% condition first.
NOTICE that the formula sheet has formulas for _____ variables and _____ variables
Categorical (top) and Quantitative (bottom)!!!!!!!!!!!!!!!!!!!
What is the Large Numbers Condition? How large?
When n is large, the sampling distribution of the sample mean -
is approximately normal. x
The sample size HAS to be at least 30 (n>30)
-
How do you find the shape of two sampling distributions and finding their mean difference?
Use the Large Numbers Condition as follows:
n > 30 and n > 30
1 - 2 -
Note 
Flashcard (31)