Please enable JavaScript.

Coggle requires JavaScript to display documents.

T-statistic (STEPS (First calculate the sample variance (or standard…

- - - - t statistic is computed using the estimated standard error. The t statistic is used as a substitute for a z-score that cannot be computed when the population variance or standard deviation is unknown.
        
        t = sample mean - population mean / (estimated) standard error
        
        Hypothesis can be concluded wrong if the hypothesized mean produces an extreme value for t.
        
        Hypothesize a value for the unknown population mean and plug the hypothesized value into the equation along with the sample mean and the estimated standard error, which are computed from the sample data
        
        To evaluate a t statistic that is obtained for a sample mean, the critical region must be located in a t distribution.
        
        There is a family of t distributions, with the exact shape of a particular distribution of t values depending on degrees of freedom. (n - 1)
        
        the critical t values depend on the value for df associated with the t test. As df increases, the shape of the t distribution approaches a normal distribution.
- - - - estimated d = mean difference / standard deviation = M - μ / s
    - - using a Confidence interval μ is an alternative method for describing the size of a treatment effect
        
        A confidence interval is a range of values that estimates the unknown population mean
        
        select a level of confidence and then look up the corresponding t values to use in the equation f
        
        For 95% confidence, use the range of t values that determine the middle 95% of the distribution
- - - - Spearman correlation measures the consistency of direction in the relationship between X and Y... the degree to which the relationship is one-directional, or monotonic
        
        Compute the Pearson correlation using the ranks
        
        Rank the X scores and the Y scores separately.
        
        Point-biserial correlation measures the strength of the relationship when one of the two variables is dichotomous
        
        the dichotomous variable is coded using values of 0 and 1, and the regular Pearson formula is applied
        
        Squaring the point-biserial correlation produces the same r² value that is obtained to measure effect size for the independent-measures t test
        
        Both variables, X and Y, are dichotomous, the phi-coefficient can be used to measure the strength of the relationship
        
        Both variables are coded 0 and 1, and the Pearson formula is used to compute the correlation.