举一反三
- 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
- 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
- In determining an interval estimate of a population mean when σ is unknown, we use a t distribution with n - 1 degrees of freedom.
- in comparing the means of two independent population , sample are randomly selected from normally distributed populations and population variances are equal, we can use paired t test for the mean difference.
内容
- 0
When testing for a difference in two population means from small samples, a pooled variance must be computed when ___________.
- 1
The difference between the sample mean and the population mean is called the sampling error.
- 2
The difference between the sample size and the population size is called the sampling error.
- 3
There is a slight difference in meaning between the two words.
- 4
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 _______.