举一反三
- 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 _______.
- 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
- 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.
- If a paired comparison test of mean differences supports rejecting the null hypothesis, then the: A: independence of the samples is statistically significant. B: standard error of the mean differences is low relative to the sample mean difference. C: difference in means is not statistically significant.
- When comparing the means of three groups and above in population, we use A: t-test B: ANOVA C: Chi-square D: Rank test
内容
- 0
The difference between the sample mean and the population mean is called the sampling error.
- 1
In a test of the mean of a population, if the population variance is: A: known, a z- distributed test statistic is appropriate. B: known, a t- distributed test statistic is appropriate. C: unknown, a z -distributed test statistic is appropriate.
- 2
The difference between the sample mean and the population mean is called the: A: population deviation. B: population standard deviation. C: standard error of the mean. D: sampling error.
- 3
The term ‘variance’ of the method ‘Analysis of Variance’ means: . A: The method is to compare the difference of population variances B: The method is to compare the difference of sample variances C: The method requires that variances of different groups should be equal D: The method calculates MS and compares MS, while MS is variance in concept E: The method calculates SS and compares SS, while SS is variance in concept
- 4
To compute an interval estimate for the difference between the means of two populations, the t distribution is restricted to small sample situations.