Loading…
Example 7.8 from Statistics, 7.3 Using the Central Limit Theorem
(part 3)
c. Find P(Σx < 200). Draw the graph.
Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.
Solution
c. The mean of the sum of 75 stress scores is (75)(3) = 225.
The standard deviation of the sum of 75 stress scores is (1.15) = 9.96.
Figure 7.6The probability that the total of 75 scores is less than 200 is about zero.
normalcdf(75,200,(75)(3),(1.15)).Reminder
The smallest total of 75 stress scores is 75, because the smallest single score is one.
How did it go?