Exam 9: A: large-Sample Tests of Hypotheses

Assuming that all necessary conditions are met, what needs to be changed in the formula so that we can use it to construct a confidence interval estimate for the population proportion p? A) B) C) D)

A sample of size 150 from population 1 has 40 successes. A sample of size 250 from population 2 has 30 successes. What is the value of the test statistic for testing the null hypothesis that the proportion of successes in population one exceeds the proportion of successes in population two by 0.05?

In testing vs. the following summary statistics are found: and Based on these results, the null hypothesis should be rejected at the significance level

In testing the difference between two population means using two independent samples, the population standard deviations are assumed to be known, and the calculated test statistic equals 2.75. If the test is two-tailed and 5% level of significance has been specified, the conclusion should be not to reject the null hypothesis.

The p-value of a statistical test is the largest value of the significance level for which the null hypothesis can be rejected.

The decision maker controls the probability of committing a Type I error.

When we test for differences between the means of two independent populations, we can use only a two-tailed test.

If you wish to conduct a hypothesis test using a small significance level , you should increase your sample size to lower the probability of making a Type II error.

A Type I error for a statistical test is committed if we reject the null hypothesis when it is true.

If we do NOT reject the null hypothesis, what are we concluding?

The test statistic that is used in testing vs. is where

With all other factors held constant, the chance of committing a Type II error increases if the true population mean is closer to the hypothesized value

From a sample of 400 items, 14 are found to be defective. In this case, what is the point estimate of the population proportion defective?

In a two-tailed test, if the p-value is less than the probability of committing a Type I error, what can you conclude?

The necessary conditions having been met, a two-tailed test is being conducted to test the difference between two population means, but your statistical software provides only a one-tail area of 0.036 as part of its output. What is the p-value for this test?

If the null hypothesis is rejected at the 0.05 level of significance, it must be rejected at the 0.01 level.

If a hypothesis test leads to incorrectly rejecting the null hypothesis, a Type II error has been committed.

The significance level in a hypothesis test for the difference between two population means is the same as the probability of committing a Type I error.

The necessary conditions having been met, a two-tailed test is being conducted for the difference between two population proportions. If the value of the test statistic is -1.35, then the p-value is 0.0885.

In testing vs. at any p-value greater than 0.025 will lead to a rejection of the null hypothesis.