MATH121 M Statistic Chapter 9 Vocabulary

Parameter

A numerical summary of a population. Its value is considered to be fixed and unchanging.

Population Parameter

Used to make it clear that the parameter is dealing with a population instead of a sample.

Statistic

A numerical summary of a sample. Its value may be different for different samples.

Sample Statistic

Synonym for Statistic.

Sample Estimate

Synonymous and reinforces the idea that a statistic often is used to estimate the corresponding population parameter.

Estimate

Synonym for Sample Estimate.

Statistical Inference

Information is used to make generalizations about a larger population. Sample statistics are used to make conclusions about population parameters.

Confidence Interval

An interval of values that the researcher is fairly sure will come true, unknown value of the population parameter.

Hypothesis Testing

Uses sample data to attempt to reject a hypothesis about the population.

Significance Testing

Same idea as Hypothesis Testing

Null Value

A value that would indicate that nothing of interest is happening.

Statistical Significance

Equivalent to rejecting the idea that the observed results are plausible if the null value is correct.

Population Proportion

A number between 0 & 1 representing the proportion with that trait.

Difference In Two Population Proportions

Used when we have two populations or have two population groups formed by a categorical variable & we want to compare some feature of the two populations.

Population Mean

With quantitative variables, one of the simplest summaries for the population is the average variable for everyone in the population.

Paired Differences

Data that are formed by taking the differences in matched pairs.

Population Mean For Paired Differences

The mean that we would get if we took differences for the entire population of possible pairs.

Independent Samples

The individuals in one sample are not coupled in any way with the individuals in the other sample.

Differences In Two Population Means

The parameter of interest is called this when we're interested in comparing the mean for the same quantitative variable in two different populations or two population groups formed by a categorical variable.

Sampling Distribution

The probability distribution of possible values of the statistic for repeated samples of the same size taken from the same population.

Standard Deviation of X-Bar

The standard deviation of the sampling distribution of a sample mean.

Standard Deviation of P-Hat

The standard deviation of the sampling distribution of a sample proportion. How far apart the sample proportion & the true population proportion are likely to be.

Standard Error

Describes the estimated standard deviation for a sampling distribution.

Sample Proportion

The proportion of trials resulting in success, or the proportion in the sample.

Normal Curve Approximation Rule for Sample Proportions

The sampling distribution for a sample proportion is approximately a normal distribution.

Sampling Distribution of P-Hat

The approximate normal distribution.

Standard Error of P-Hat

An estimated version of the Standard Deviation of P-Hat.

Sampling Distribution of P-Hat1 minus P-Hat2

The difference in population proportions.

Standard Deviation of P-Hat1 minus P-Hat2

The Standard Deviation when it comes to the sampling distribution of P-Hat1 minus P-Hat2.

Standard Error of P-Hat1 minus P-Hat2

When we don't know the population proportions, we use sample proportions instead.

Normal Curve Approximation Rule for Sample Means

If numerous random samples of the same size n are taken, the distribution of possible values of X-Bar is approximately normal.

Sampling Distribution of X-Bar

The approximate normal distribution of X-Bar.

Sampling Distribution of The Mean

Synonym for the Sampling Distribution of X-Bar.

Standard Deviation of The Sample Means

The parameter Sigma is a measure of the variability among the individual measurements within the population.

Standard Error Of The Mean

The standard error measures roughly how much, on average the sample mean X-Bar is in error as an estimate of the population mean Mu.

Dependent Samples

Data that are collected as matched pairs are sometimes called this because the two observations are not statistically independent of each other.

Sampling Distribution of D-Bar

The population mean of the differences.

Standard Deviation of D-Bar

(Sigma D) / (Square Root of N)

Standard Error of D-Bar

Used to estimate the standard deviation when Sigma D is not known.

Sampling Distribution of X-Bar1 minus X-Bar2

Difference in population means.

Standard Deviation of X-Bar1 minus X-Bar2

The standard deviation when it comes to the sampling distribution of X-Bar1 minus X-Bar2.

Standard Error of X-Bar1 minus X-Bar2

When we don't know the population standard deviations we use the sample standard deviation instead.

Standardized Statistic

Z = (Sample Statistic - Population Parameter) / S.D. (Sample Statistic)

Standardized Z-Statistic

Used to assess the difference between an observed sample proportion (P-Hat) & a possible value for the population proportion (P).

Student's T-Distribution

Distribution is called this when under certain conditions, it has a probability distribution.

Degrees Of Freedom (DF)

A parameter is called this when there's an association w/any t-distribution.

Standardized T-Statistic

t = (Sample Statistic - Population Parameter) / S.E. (Sample Statistic)

Law of Large Numbers

Guarantees that the sample mean X-Bar will eventually get "close" to the population mean Mu no matter how small a difference you use to define close.

Central Limit Theorem

States that if n is sufficiently large, the sample means of random samples from a population with mean Mu & finite standard deviation Sigma are approximately normally distributed with mean Mu & standard deviation (Sigma) / (Square Root of n)