2.13.2.3 ttest1

Brief Information

One-Sample t-test

Command Line Usage

1. ttest1 irng:=Col(A);

2. ttest1 irng:=Col(A) mean:=10 tail:=1;

3. ttest1 irng:=Col(A) alpha:=0.05;

3. ttest1 irng:=Col(A) prob:=myprob;

Variables

Display
Name
Variable
Name
I/O
and
Type
Default
Value
Description
Input irng

Input

Range

<active>

This variable specifies the input data range.

Hypothetical mean mean

Input

double

0

This variable specifies a value for the null hypothesis mean

Tail tail

Input

int

two

Alternative hypothesis specified by the tail. (Suppose m is the sample mean and m0 is the hypothetical mean.)

Option list

  • two:Two Tailed
H0: m <> m0
Test whether the sample mean equals to the hypothetical mean
  • upperUpper Tailed
H0: m > m0
Test whether the sample mean is larger than the hypothetical mean
  • lower:Lower Tailed
H0: m < m0
Test whether the sample mean is less than the hypothetical mean.
Significance level alpha

Input

double

0.05

Set the significance level of the test

Statistic stat

Output

double

<unassigned>

This variable specifies the output for the t-test statistic

Degrees of freedom df

Output

double

<unassigned>

This variable specifies the output for the degrees of freedom for the sample data

P-value prob

Output

double

<unassigned>

This variable specifies the output for the associated p-value of the test.

Lower confidence limit lcl

Output

double

<unassigned>

This variable specifies the output for the lower confidence limit for the hypothetical mean of the sample data.

Upper confidence limit ucl

Output

double

<unassigned>

This variable specifies the output for the upper confidence limit for the hypothetical mean of the sample data.

Description

This function is LabTalk accessing only and performs one-sample t-test for a given dataset.

The one-sample Student's t-Test determines whether or not the mean of a sample taken from a normally distributed population is consistent with the hypothetical value for a given confidence level. By choosing a one- or two-tailed t-test, you can test how likely it is that the sample mean is greater than, less than, or equal to the true population mean. Note that the one-sample t-test is appropriate when the standard deviation of the entire population is unknown.

The t statistic value and p-value will be calculated to decide whether or not to reject the null hypothesis. The p-value is the probability that null hypothesis is true, and a small p-value suggests that you should reject it.

The confidence interval provides lower and upper limits for the possible value of the population mean. For a given significance level, \alpha., this interval indicates we have 100 \times(1-\alpha) % confidence to say the true population mean falls within the interval.

Algorithm

Detail algorithms please read the help of OneSampletTest

References

Snedecor, George W. and Cochran, William G. (1989), Statistical Methods, Eighth Edition, Iowa State University Press.

Related X-Functions

ttest2, ttestpair