Engineering Data Analysis (CEM – 120)
Quiz # 1
Instruction: Do not write anything on the test questionnaire. Use separate sheet.
Problem 1.
In the frequency distribution table shown below are the numbers of books read by 28
students in a mathematics class. Answer the following question/s. Support your answer.
No. of books frequency
0 – 2 2
3 – 5 6
6 – 8 12
9 – 11 5
12 – 14 3
N = 28
a. What is the average number of books used by the students?
b. How many books that are majority used by the students?
c. Show the relationship between the three measures of centrality.
d. What is the standard deviation?
e. Construct a box plot showing the necessary data for a boxplot.
f. What is the P10, Q5, D9?
Problem 2.
a. Find the area of the curve if P(0 < z < 1.69).
b. Find Z1 such that P(Z1 < Z < 2.5) = 0.7672
Problem 3. Application of the normal curve.
A researcher wishes to select civil engineering students applicants in the middle 50% of the
population based on their percentile score. If the average percentile score is 120 and the standard
is 0.8. What will be the lowest and the highest percentile score to qualify in the study? Assuming
normally distributed.