Test statistic in r

A critical-T value is a “cut-off point” on the t distribution. A t-distribution is a probability distribution that is used to calculate population parameters when the sample size is small and when the population variance is unknown.

T values are used to analyze whether to support or reject a null hypothesis. 

After conducting a t-test, we get its statistics as result. In order to determine the significance of the result, we compare the t- score obtained by a critical t value.

 If the absolute value of the t-score is greater than the t critical value, then the results of the test are statistically significant.

Formula:

t = [ x̄ - μ ] / [ s / sqrt( n ) ]

where,

• t = t score
• x̄ = sample mean,
• μ = population mean,
• s = standard deviation of the sample,
• n = sample size 

Function used:

In order to find the T Critical value we make use of qt() function provided in R Programming Language. 

Syntax: qt(p=conf_value, df= df_value, lower.tail=True/False)

Parameters:

• p:- Confidence level
• df: degrees of fre
  how to calculate t test in r
  how to calculate t value in research