Answer:
To solve difference in means and proportions problems, you can use a 5-step plan. Here is the correct order to follow:
1. Identify all required values: Before you can solve the problem, you need to know what information is given and what you are looking for. For example, you might need the sample means, sample sizes, or population proportions.
2. Find the required value of Z or t: Depending on the problem, you will use either the Z-score or t-score to find the critical value. This value helps determine if the difference you observe is statistically significant.
3. Determine the value of x-bar 1 minus x-bar 2 (or p1-p2): Calculate the difference between the means (x-bar 1 - x-bar 2) or proportions (p1 - p2). This represents the observed difference in the two groups you are comparing.
4. Plug the values and simplify: Substitute the known values into the appropriate formula and simplify the expression. For example, you might use the formula for the standard error of the difference in means or the standard error of the difference in proportions.
5. Find and interpret the test statistic: Calculate the test statistic by dividing the observed difference by the standard error. Compare this value to the critical value from step 2. If the test statistic is greater than the critical value, you can conclude that the observed difference is statistically significant.