6,7 and 8 please!!!

Critical Thinking Challenges Sometimes a researcher must decide whether a variable is 2. Find the cumulative frequencies for each class, and normally distributed. There are several ways to do this. One place the results in the third column. simple but very subjective method uses special graph paper, which is called normal probability paper, For the distribution 3. Find the cumulative percents for each class by dividing of systolic blood pressure readings given in Chapter 3 of the each cumulative frequency by 200 (the total frequencies) text, the following method can be used: and multiplying by 100%. (For the first class, it would be 24/200 X 100% = 12%.) Place these values in the last 1. Make a table, as shown. column. Cumulative 4. Using the normal probability paper shown in Table 6-3, Cumulative percent label the x axis with the class boundaries as shown and Boundaries Frequency frequency frequency plot the percents. 89.5-104.5 24 104.5-119.5 62 5. If the points fall approximately in a straight line, it can 119.5-134.5 be concluded that the distribution is normal. Do you feel 134.5-149.5 26 that this distribution is approximately normal? Explain 149.5-164.5 12 your answer. 164.5-179.5 200 6. To find an approximation of the mean or median, draw a horizontal line from the 50% point on the y axis over TABLE 6-3 Normal Probability Paper 80 40 50 60 70 30 20 10 89.5 104.5 119.5 134.5 149.5 164.5 179.5 Answers to Applying the Concepts 367 to the curve and then a vertical line down to the x axis. 16 and 84% values on the y axis. Subtract these two Compare this approximation of the mean with the values and divide the result by 2. Compare this approxi- computed mean. mate standard deviation to the computed standard 7. To find an approximation of the standard deviation, deviation locate the values on the x axis that correspond to the 8. Explain why the method used in step 7 works