Consider the accompanying data on flexural strength (MPa) for concrete beams of
ID: 3316524 • Letter: C
Question
Consider the accompanying data on flexural strength (MPa) for concrete beams of a certain type. 7.2 6.8 8.1 9.0 11.8 7.3 10.7 7.0 7.9 7.7 9.77.4 6.5 7.8 11.3 6.0 7.0 7.7 6.8 8.9 6.3 6.3 9.7 7.4 8.77.8 11.6 (a) Calculate a point estimate of the mean value of strength for the conceptual population of all beams manufactured in this fashion. [Hint: your answer to three decimal places.) 9-220.4.] (Round MPa State which estimator you used s/x (b) Calculate a point estimate of the strength value that separates the weakest 50% of all such beams from the strongest 50% MPa State which estimator you used. s/xExplanation / Answer
Solution:-
a) mean = sum of terms/number of terms = 220.4/27 = 8.163 MPa
=> option E.
b) we use the sample median, = 7.7 (the middle observation when arranged order)
=> option B.
c) standard deviation = 1.664 MPa
=> option C. This estimate describes the spread of the data
=> option C. s
d) p=4/27=0.148
e) => 1.664/8.163 = 0.204
=> option A.