Busan Topic 2 Flashcards
Consistency
Probability that a sample statistic will be close to the population parameter aprroaches 1 as the sample size increase
Population
The universe. The data that hasnt been completely examin but what our conclusions refer to. Indicated by N
Sample
The portion of the popualtion that is avaible for analysis. INdicated by lower case n
Parameter
A charaterictic of a population. ed population mean and population standard deviation
Sample Statistic
A meaure derived from the sample data. eg sample mean and sample deviation
Statistical Inference
the process of using the sample to draw conclusions about the population parameters
Descriptive Statistic
Stats that summerize a sample of numerical data in terms of averages and over measures
Expected Value E(X) or mean
measure of central tendency
Median
The distrubution of two halves
Mode
The value with the greatest probability
Variance var(X)
measure of dispersion(spread)
Standard Deviation
meaures dispersion in the same units as the random variable, and is the square root of the variance.
An efficent estimator
masures how spread out the estimates around the true population parameter
A good estimator is…
unbiased, efficent and consistent
Estimator versus estimate
AN estimate is the actual numerical value obtained from an estimator
Sample design features
1) Random
2) Various techniques
point estimate
interval estimate
confidence interval
a plausible range of values for the population parameter
Proportions
Sample proportions can be a measure instead of the sample mean
Z - Score
Indicates how many standard deviations away from the mean a value lies.
Central Limit Theorem
Width of an Interval- advantage and drawback
Draw back is that it makes it harder to draw meaningful convulsion due to lack of precision
Hypothesis Testing
Does the data support some belief (hypothesis) about the value of the population parameter
Estimation and hypothesis testing
Ehtically it is better to provide a confidence interval than just a point estimate because too much weight can be put on a point estimate
The high your confidence percentage will be… the ___ your confidence interval will be
larger
When to use a t value
If sample is less than 30
If population variance is unknown
Z values can be used when
Population variance is known
Sample is >= 3o
Population is unknown but large enough
One tailed test
The allow for an alternative hypothesis to be onsided
Rejection rules
When its assumes that Ho is correct, we test this to see if its the case or not
