7,8 Flashcards
Normal distribution mena is
Std is
1 std
2 std
3 std
0
1
68%
95%
99.7%
Normal distribution is for…also called…
Total area under the curve is..
Mean,mode,median
Continuous
Gaussian/bell shaped
1
Are equal
Z score
When wanting to know the upper 5 percent
X-mean/std
Search for 0.95 in z table to know the z score and solve for x not z
Sampling distribution
The freq of getting different values while trying different samples to evaluate a population
Ux-
Mean
Mean for each sample/n (freq).
O^2x-
Variance
Sum(Each mean- sampling mean)^2/n
Normally distributed sample will have
Normal distribution of means
Mean of sampling is the mean of population
Variance of sampling is the variance of population
Non normally distributed
Central limit theorum
Central limit theorum
Mean of sampling distribution is identical to population mean
Std of sampling = standard error
When n is large enough the sampling distribution is nearly normal
What is standard error
Std/√n
As long as n is larger than… Standard error of mean is…
If n is large enough
Larger n is needed for
1, smaller than standard deviation of population
The distribution of sample means will be normal
Farther non normally distributed populations means to be normal
Confidence level
X- +- z(1-a/2) standard error
Z score* confidence level*standard error
The lower the..the lower the..
Variation
Confidence level interval
Statistical hypothesis vs hypothesis test
Why important to hypothesis test
An argument about a specific statistical question can be true or wrong
Standard procedure for testing a claim
Objective framework for making decisions using stats, uniform decision making criteria
Formulating a hypothesis
Null and alternative
Test static
Sig level
Critical region
Conclusion
