Statistical Inference Flashcards
Parameter
A characteristic of a population
Statistic
A number computed from the sample
Estimation Process
Procedure of guessing an unknown parameter value using the observed values from samples
Estimate
A specific guess or value computed from a sample
Point Estimation
Gives a single value as an estimate of the unknown parameter and makes no allowance for the uncertainty of the value’s accuracy
Interval Estimation
Recognizes the uncertainty of the estimate’s accuracy and compensates for it by specifying a range of values around the estimate within which the population parameter may actually lie
Margin of Error
The range around the point estimate
Sampling Distribution
The distribution of estimates from all possible samples of the same size from the same population
Unbiasedness
Refers to the idea that a statistic is expected to give values centered on the unknown parameter value
Variability
Refers to the degree of variation in a statistic’s values
Bias
Indicates that our guess is systematically wrong
Inefficiency
Indicates that our guess is wrong unsystematically
Confidence Intervals
Consists of two numbers between which we are reasonably certain our true parameter will fall
Statistical Hypothesis
A statement that is assumed to be true until proven otherwise
Alternative Hypothesis
A statement about the parameter that must be true if the null hypothesis is false
Test Statistic (TS)
A statistic computed from the sampled data and used in the process of testing a hypothesis
P-Value
The probability that we would observe a test statistic value as least as extreme as the one computed from the sample if the null hypothesis were true
Type I Error
Rejecting the null hypothesis when it is true
Type II Error
Failing to reject the null hypothesis when it is false
Rejection Region (RR)/Critical Region (CR)
The set of test statistic values for which we would reject the null hypothesis
Non-Rejection Region
The set of test statistic values for which we should fail to reject the null hypothesis
Critical Value (CV)
The value of a test statistic that gives the boundary between the rejection and non-rejection region
Conditions For Making A Test/Interval
- SRS
- Independence
- Normality
Observed Frequency
The number of measurements from one experiment falling into that particular cell
Expected Frequency
The number of measurements expected to fall into that cell
