How much difference is reasonable to expect between the two sample?
how much difference is reasonable to expect between the two sample means if there is no treatment effect In a hypothesis test, the only way to obtain a value of zero for the independent measures t statistic is when M1 = M2.
Is it possible to get significant differences between treatments with small variances?
In an independent-measures t test if the sample variances are very large, it is NOT/VERY possible to obtain a significant difference between treatments even if the actual mean difference is very small. NOT One sample has n = 7 scores with SS = 40, and a second sample has n = 5 scores with SS = 80. The pooled variance 120/10 = 12 True or false?
When the distribution of sample means will not be normal?
The distribution of sample means will not be normal when it is based on small samples (n < 30) selected from a population that is not normal. 5. A population has a standard deviation of r = 30.
Can you have a t test with a large sample variances?
In an independent-measures t test if the sample variances are very large, it is NOT/VERY possible to obtain a significant difference between treatments even if the actual mean difference is very small. NOT One sample has n = 7 scores with SS = 40, and a second sample has n = 5 scores with SS = 80.
What happens when there is no treatment effect?
In other words, if the treatment had no effect, a person would have the same score, no matter which group he or she was assigned to. Thus, even after the data have been collected, the mean of what we have called Group One would have the same expectation after we shuffled subjects among groups.
How does difference between the means of our sample impact the t-value?
A t-value of 0 indicates that the sample results exactly equal the null hypothesis. As the difference between the sample data and the null hypothesis increases, the absolute value of the t-value increases.
How do you tell if means are significantly different?
When the P-value is less than 0.05 (P<0.05), the conclusion is that the two means are significantly different.
Is to test if there is any significant difference between the means of two or more groups?
t-testA t-test is a type of inferential statistic used to determine if there is a significant difference between the means of two groups, which may be related in certain features. The t-test is one of many tests used for the purpose of hypothesis testing in statistics. Calculating a t-test requires three key data values.
What is the result of taking the difference between sample means minus the null hypothesized difference divided by the standard error of the difference between means?
The t-statistic is estimated as the difference between the two sample means, minus the difference between the true population means, divided by the estimated standard error of the difference between the sample means. For a null hypothesis of no difference, the difference between the true population means is zero.
What is the difference between a one-sample t-test and a two sample t-test?
If you are studying one group, use a paired t-test to compare the group mean over time or after an intervention, or use a one-sample t-test to compare the group mean to a standard value. If you are studying two groups, use a two-sample t-test. If you want to know only whether a difference exists, use a two-tailed test.
How do you compare different means?
Comparison of means tests helps you determine if your groups have similar means....The four major ways of comparing means from data that is assumed to be normally distributed are:Independent Samples T-Test. ... One sample T-Test. ... Paired Samples T-Test. ... One way Analysis of Variance (ANOVA).
What should be done if the ANOVA results show that there is no significant difference between the groups being compared?
If you had a more complex structure and the entire ANOVA showed non-significant differences, then you would make an omnibus conclusion that you did not detect any differences. You would use a post hoc (after the fact) test only if one or more sources of variance was significant.
What does it mean when results are not statistically significant?
This means that the results are considered to be „statistically non-significant‟ if the analysis shows that differences as large as (or larger than) the observed difference would be expected to occur by chance more than one out of twenty times (p > 0.05).
When comparing more than two condition means Why should an analysis of variance be used instead of multiple t-tests?
when comparing more than two treatment means, why should you use an analysis of variance instead of using several t tests? using several t tests increases the risk of experiment-wise Type I error.
Which one is used to test the significance of the difference between the means of two random samples of sizes less than 30?
Please, use the t-test statistics to test for statistical significance for your sample.
How do you compare the variance between two groups?
In order to compare multiple groups at once, we can look at the ANOVA, or Analysis of Variance. Unlike the t-test, it compares the variance within each sample relative to the variance between the samples.
What is the t/f of an independent-measures study?
T/F: An independent-measures study produces t(10) = 3.00, p < .05. For this study, if effect size is measured with r2, then r2 = 3/13.
What happens to the pooled variance if two sample variances are not equal?
T/F: If two sample variances are not equal, the pooled variance will be closer to the larger of the two variances.
What is the T/F assumption?
T/F: The homogeneity of variance assumption states that the two population variances are equal.
What is the interval between M1 and M2?
Estimate that m1 - m2 is in an interval between 2 and 10 with 95% confidence
What is the T/F statistic?
T/F: For an independent-measures t statistic, the estimated standard error measures how much difference is reasonable to expect between the sample means for two samples selected from the same population.
What happens if two samples are the same size?
If two samples are the same size, the the pooled variance will be
Can a t-test show significant difference between treatments?
In an independent-measures t test if the sample variances are very large, it is NOT/VERY possible to obtain a significant difference between treatments even if the actual mean difference is very small.
When is the average grade recorded?
classroom. At the end of the school year, the average grade is recorded for each
What is the value of t (28)?
for an independent-measures design with t (28) = 2.27.
Is treatment significantly greater than the scores in the second?
treatment are significantly greater than the scores in the second. (Note: Because
What is possible sample mean?
possible sample means is simply the distribution of sample means, which is normal, with a
What is distribution of sample?
1. a. The distribution of sample means consists of the sample means for all the possible random samples of a specific size (n) from a specific population.
What is the mean of a population with a mean of p = 60?
A population forms a normal distribution with a mean of p = 60 and a standard deviation
What is the standard error of M?
c. The standard error of M is the standard deviation of the distribution of sample means (σM = σ/n).
What is the mean of the distribution of sample mean?
The mean of the distribution of sample means is equal to the mean of the population of scores, p, and is called the
What is the p value of a positively skewed distribution?
3. A positively skewed distribution has p = 60 and a = 8.
What is natural discrepancy?
natural discrepancy, or amount of error, between a sample statistic and its corresponding population parameter.
Is sample mean close to population mean?
the sample mean is close to the population mean.
Can you use unit normal table to find probability?
Therefore, you cannot use the unit normal table, and it is impossible to find the probability.
Does expected value depend on sample size?
2. False. The expected value does not depend on sample size.
