Confidence intervals, Confidence intervals ,18-22 – HP 50g Graphing Calculator User Manual

Page 589

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Page 18-22

L @)STAT @PLOT @SCATR

produce scattergram of y vs. x

@STATL

show line for log fitting

Θ To return to STAT menu use: L@)STAT
Θ To get your variable menu back use: J.

Confidence intervals

Statistical inference is the process of making conclusions about a population
based on information from sample data. In order for the sample data to be
meaningful, the sample must be random, i.e., the selection of a particular
sample must have the same probability as that of any other possible sample out
of a given population. The following are some terms relevant to the concept of
random sampling:

Θ Population: collection of all conceivable observations of a process or

attribute of a component.

Θ Sample: sub-set of a population.
Θ Random sample: a sample representative of the population.
Θ Random variable: real-valued function defined on a sample space. Could

be discrete or continuous.

If the population follows a certain probability distribution that depends on a
parameter

θ, a random sample of observations (X

1

,X

2

,X

3

,... , X

n

), of size n,

can be used to estimate

θ.

Θ Sampling distribution: the joint probability distribution of X

1

,X

2

,X

3

,... , X

n

.

Θ A statistic: any function of the observations that is quantifiable and does not

contain any unknown parameters. A statistic is a random variable that
provides a means of estimation.

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