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The common assumptions made when doing a t-test include those regarding the scale of measurement, random sampling, normality of data distribution, adequacy of sample size, and equality of variance in standard deviation.
Two-sample t-test assumptions Data in each group must be obtained via a random sample from the population. Data in each group are normally distributed. Data values are continuous. The variances for the two independent groups are equal.
What does it mean if a paired t test is not significant?
You do not have enough evidence to conclude that the difference between the population means is statistically significant….Step 2: Determine whether the difference is statistically significant.
| T-Value | P-Value |
|---|---|
| 3.02 | 0.0070 |
How do you test for missing values in SAS?
Check for missing numeric values If x <=. z then PUT “x is missing”; The MISSING function accepts either a character or numeric variable as the argument and returns the value 1 if the argument contains a missing value or zero otherwise.
What are the assumptions of one sample t test?
For the results of a one sample t-test to be valid, the following assumptions should be met: The variable under study should be either an interval or ratio variable. The observations in the sample should be independent. The variable under study should be approximately normally distributed.
What do you need to know about paired samples t test?
For the paired samples t-test, these are independent observations or, more precisely, independent and identically distributed variables; the difference scores between the two variables must be normally distributed in our population.
Which is equivalent to one sample t test?
Technically, a paired samples t-test is equivalent to a one sample t-test on difference scores. It therefore requires the same 2 assumptions.
When to reject the null hypothesis in one sample t test?
If the p-value that corresponds to the test statistic t with (n-1) degrees of freedom is less than your chosen significance level (common choices are 0.10, 0.05, and 0.01) then you can reject the null hypothesis. One Sample t-test: Assumptions For the results of a one sample t-test to be valid, the following assumptions should be met: