Exam 9: Hypothesis Testing II: the Two-Sample Case

A researcher conducted a survey to determine if older people have different feelings about abortion than younger people.He used an alpha level of 0.05 (Z critical = $\pm$ 1.96)to test for significance and found that his computed test statistic was 2.76.Which of the following conclusions is justified?

A scale measuring confidence in the media was administered to a sample.Is there a statistically significant difference between Democrats and Republicans on the scale? Higher scores on the scale indicate greater confidence.Use the five step model and write a sentence or two interpreting your results. =8.5 =7.8 =1.5 =1.1 =36 =35

For all tests of hypothesis,the probability of rejecting the null hypothesis is a function of

When solving the formula for finding Z(obtained)with sample proportions in the two-sample case,we must first estimate

In testing for the significance of the difference between two sample means when the sample size is small,we may assume equal population variances if

When testing for the significance of the difference between sample means with small samples,the proper sampling distribution is

When testing hypotheses using two small samples,the t distribution may be used only after the additional assumption that

To maximize the probability of rejecting the null hypothesis,use

From a university population,random samples of 45 seniors and 37 freshmen have been given a scale that measures sexual experiences.The freshmen report an average of 1.6 sexual partners over their lifetimes while seniors report an average of 2.5 partners.The t (obtained)for this difference was -3.56 while the t (critical)was $\pm$ 2.34.What can be concluded?

When testing for the significance of the difference between two samples,which is the proper assumption for step 1?

To satisfy the requirement of independent random sampling,the researcher

Four test of significance were conducted on the same set of results: For test 1: alpha = 0.05,two-tailed test. For test 2: alpha = 0.10,one-tailed test. For test 3: alpha = 0.01,two-tailed test. For test 4: alpha = 0.01,one-tailed test. Which test is most likely to result in a rejection of the null hypothesis?

When testing for the significance of the difference between two sample means,the standard deviation of the sampling distribution is estimated using

A difference between samples that is shown to be statistically significant is always

If a difference between random samples is not statistically significant,it is probably ____.On the other hand,a statistically significant difference is not necessarily ____.

When testing for the significance of the difference between two samples,the null hypothesis states that the ____ are the same

Is there a statistically significant difference between males and females in terms of newspaper readership? The proportion of each sex that says they read a newspaper daily is reported below.Results are from a nationally representative sample.Use the five step model and write a sentence or two interpreting your results. =56 =.56 =786 =965

When testing for the significance of the difference between two sample means,the null hypothesis is that

For testing the difference between two sample means,the level of measurement is assumed to be

Since critical values of t vary by sample size,before using the t table we must first calculate