How to Calculate a T-Test

104 16
    • 1). Define the mean of a population sample. The mean of a population sample is the sum of the scores in that sample divided by the number of members in the sample. This may be expressed mathematically as μ = Σ xi/n, where μ is the population mean, xi is the ith score in the sample and n is the number of members in the sample.

    • 2). Define the standard deviation of a sample. A t-test measures scores in units of standard deviation, which may be represented mathematically as s = ( Σ ( xi - x )2 / ( n - 1 ) ) ^(1/2), where s is the standard deviation of the sample, xi is the ith element of the sample, x is the sample mean and n is the number of elements of the sample population.

    • 3). Derive scores for the t-test. This is given by t = ( x - X ) / ( s / n^(1/2)), where t is the t-score, x is the mean of the sample, X is the mean of the population, s is the standard deviation of the sample and n is the number of members in the sample.

    • 4). Learn the properties for the distribution of a t-test. A t-distribution has one less degree of freedom than the number of members in the sample. A t-distribution's mean is 0, and its variance is f / ( f - 2 ), where f is the number of degrees of freedom of the distribution. Note that this definition of variance means that the sample for a t-test must have at least four members.

    • 5). Use a t-test when the standard deviation of the population is unknown. The sample size may be small so long as it has an approximately normal distribution.

Source...
Subscribe to our newsletter
Sign up here to get the latest news, updates and special offers delivered directly to your inbox.
You can unsubscribe at any time

Leave A Reply

Your email address will not be published.