This exercise is based on the following information, gathered from student testing of a statistical software package called MODSTAT. Students were asked to complete certain tasks using the software, without any instructions. The results were as follows. (Assume that the time for each task is normally distributed.) It can be shown that if X and Y are independent normal random variables with means 
and ![]()
src="https://sciemce.com/media/2/ppg__cognero__9.5_Normal_Distributions__media__8307352f-2871-4242-8b8c-f520d6281ef2.PNG" style="vertical-align:middle;" /> and standard deviations 
and 
respectively, then their sum 
is also normally distributed and has mean 
and standard deviation 
. Assuming that the time it takes a student to complete each task is independent of the others, find the probability that a student will take at least 20 minutes to complete both Tasks 3 and 4. Round your answer to four decimal places.
TaskMean Time(minutes)StandardDeviationTask 1: Descriptive Analysis of Data11.45.0Task 2: Standardizing Scores11.99.0Task 3: Poisson Probability Table7.54.1Task 4: Areas Under Normal Curve9.55.9?
A. 0.3382
B. ?0.6638
C. ?0.6764
D. ?0.3372
E. ?0.6628
Answer: D
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Find the margin of error for the survey results described. In a poll of 1757 adults, 30% said that they exercised regularly.Give your answer as a percentage to one decimal place.
A. 4.8% B. 2.4% C. 1.2% D. 0.1%
If the point (7, 3 ) is on the graph of an even function, what other point must also be on the graph? Select the correct answer.
a. (–7, –3) b. (7, –3) c. (0, 0) d. (–7, 3) e. None of these
Express the sum using summation notation.5 + 
+ 
+ ... + 
A. 
B. 
C.
D.
Graph the function by starting with a function from the library of functions and then using the techniques of shifting, compressing, stretching, and/or reflecting.g(x) = 
A. 
B. 
C. 
D. 