When testing for a difference in two population means from small samples, a pooled variance must be computed when ___________.
举一反三
- Analysis of Variance (ANOVA) is a test for the difference in . A: means of two or more samples B: means of three or more samples C: vairance of three or more smaples D: means of two or more populations E: variance of two or more populations
- When the sample sizes are equal, the pooled variance of the two groups is the average of the two sample variances.
- A researcher is interested in testing to determine if the mean of population one is greater than the mean of population two. The null hypothesis is that there is no difference in the population means (i.e. the difference is zero). The alternative hypothesis is that there is a difference (i.e. the difference is not equal to zero). He randomly selects a sample of 9 items from population one resulting in a mean of 14.3 and a standard deviation of 3.4. He randomly selects a sample of 14 items from population two resulting in a mean of 11.8 and a standard deviation 2.9. He is using an alpha value of .10 to conduct this test. Assuming that the populations are normally distributed, the critical t-value from the table is _______.
- To compute an interval estimate for the difference between the means of two populations, the t distribution __ A: is restricted to small sample situations. B: is not restricted to small sample situations. C: can be applied when the populations have equal means. D: can be applied only when the populations have equal standard deviations.
- A researcher wants to estimate the difference in the means of two populations. A random sample of 36 items from the first population results in a sample mean of 430. A random sample of 49 items from t