# To conduct a runs test on a sample, perform the following steps:

The appropriate formula for the test of hypothesis depends on the sample size. The formulas are shown below and are identical to those we presented for estimating the mean of a single sample presented (e.g., when comparing against an external or historical control), except here we focus on difference scores.

## An Application: Suppose we wish to test the null hypothesis

### THE TWO STEP FLOW AND MULTI STEP FLOW THEORY…

We now substitute the sample data into the formula for the test statistic identified in Step 2. Before substituting, we will first compute Sp, the pooled estimate of the common standard deviation.

### “We would urge that the Katz- Lazarsfeld two-step flow hypothesis, ..

Again, the χ^{2} test of independence is used to test whether the distribution of the outcome variable is similar across the comparison groups. Here we rejected H_{0} and concluded that the distribution of exercise is not independent of living arrangement, or that there is a relationship between living arrangement and exercise. The test provides an overall assessment of statistical significance. When the null hypothesis is rejected, it is important to review the sample data to understand the nature of the relationship. Consider again the sample data.

## A revision of the two-step flow of communications hypothesis

Consider again the NCHS-reported mean total cholesterol level in 2002 for all adults of 203. Suppose a new drug is proposed to lower total cholesterol. A study is designed to evaluate the efficacy of the drug in lowering cholesterol. Fifteen patients are enrolled in the study and asked to take the new drug for 6 weeks. At the end of 6 weeks, each patient's total cholesterol level is measured and the sample statistics are as follows: n=15, x̄ =195.9 and s=28.7. Is there statistical evidence of a reduction in mean total cholesterol in patients after using the new drug for 6 weeks? We will run the test using the five-step approach.

## CiteSeerX — SCHEMATIC OF THE TWO-STEP FLOW MODEL OF INFLUENCE

Or, it might be that we would have to go backseveral steps before we found the link between the interpersonal networks ofpublic affairs opinion and disproportionate mass media effect Compared withthe realm of fashions at any rate, one is led to suspect that the chain ofinterpersonal influence is longer in the realm of public affairs and that"inside dope" as well as influencing in specific influence episodesis much more a person-to-person affair.