Application Guide
336 Lists&Spreadsheet Application
Confidence Intervals
Supported Confidence Intervals
The following confidence intervals are available from the Lists&Spreadsheets
application. For more information regarding these functions, see the TI-Nspire™
Reference Guide.
z Interval (zInterval)
Computes a confidence interval for an unknown population mean, m, when the
population standard deviation, s, is known. The computed confidence interval depends
on the user-specified confidence level.
This test is useful in determining how far from a population mean a sample mean can
get before indicating a significant deviation.
t Interval (tInterval)
Computes a confidence interval for an unknown population mean, m, when the
population standard deviation, s, is unknown. The computed confidence interval
depends on the user-specified confidence level.
This test is useful in examining whether the confidence interval associated with a
confidence level contains the value assumed in the hypothesis. Like the z Interval, this
test helps you determine how far from a population mean a sample mean can get
before indicating a significant deviation when the population mean is unknown.
2-Sample z Interval (zInterval_2Samp)
Computes a confidence interval for the difference between two population means
(m
1
Nm
2
) when both population standard deviations (s
1
and s
2
) are known. The
computed confidence interval depends on the user-specified confidence level.
This test is useful in determining if there is statistical significance between the means
of two samples from the same population. For example, this test could determine
whether there is significance between the mean college entrance test score of female
students and the mean of college entrance test score of male students at the same
school.
2-Sample t Interval (tInterval_2Samp)
Computes a confidence interval for the difference between two population means
(m
1
Nm
2
) when both population standard deviations (s
1
and s
2
) are unknown. The
computed confidence interval depends on the user-specified confidence level.
This test is useful in determining if there is statistical significance between the means
of two samples from the same population. It is used instead of the 2-sample z
confidence interval in situations where the population is too large to measure to
determine the standard deviation.