Stats Exam 3 Cedarville University/ Daryl Smith

inferential statistics

Using data analysis to infer properties of an underlying distribution of prbability

Point Estimate

A single value which determines the best estimate or best guess of a parameter

Confidence interval

refers to the probability that a population parameter will fall between two set values

Confidence level

the probability that the value of a parameter falls within a specified range of values.

Critical value

The dividing point between the region where the null hypothesis is rejected and the region where it is not rejected.

margin of error

amount allowed for miscalculation or change in circumstance

Analyzing polls

1. Random Sample

2. Confidence level should be provided

3. The Sample size should be provided

4. the quality of poll results depend on sampling method and size of sample(population size is no factor)

Sample Size

Find Sample Size

X = Zα/22 p(1-p) / MOE2

Best estimate of population mean

normality

should appear like a bell curve

n > 30

need to be greater than 30 so there are no outliers

Student t distribution

commonly just called t-distribution (found with A-3)

Construct Confidence Interval

x ± E

hypothesis

is a claim or statement about a property or a population

hypothesis test/test of significance

is a procedure for testing a claim about a property of a population

test statistic

describes how far your observed data is from the null hypothesis

two tailed

both sides of bell curve

Tailed test determined by

which way the tail points (tells the tale)

what do you compare p value to

a significance level

Type I error

Rejecting null hypothesis when it is true

Type II error

FTR when it's false

dependent

1. Before and After

2. Comparing (Pairs)

3.Twins