12. A researcher wishes to represent the percentage of students in the department of statistics using a
pie graph. If the percentage of statistical department students is 25%, then their corresponding
degree of the angle on the pie graph is .........
a) 300
b) 1080
c) 900
d) 1800
>>> هنا بالنظر نعرف .. نقول الـ 100% ربعها 25%
والدائره اذا قسمناها ارباع كل ربع بيكون زاويته 90 درجه
the range of the data set -3, -7, -13, 0, -1 is .........
a) -13
b) 13
c) 2
d) 12
>>> r=h-l=0-(-13)=13
21. If a sample of data has mean 25 and variance 25, then its coefficient of variation is .........
a) 1%
b) 0.2%
c) 20%
d) 100%
>>> من قاعدة coefficient variation .. واحنا عارفين اننا نحتاج ستاندرد ديفييشن اللي هي جذر الفارينس
28. Calculate the standard deviation for this sample:
2, 5, 3, 5, 4
a) 4.3
b) 18.8
c) 1.7
d) 1.3
>>> من قاعدة standard deviation
مجموع x = 19 .. وطبعا هو يبيها بالتربيع يعني = 316
مجموع x تربيع = 79
n=5
41. A student scored 82 on an arabic exam that had a mean of 88 and a standard deviation of 6; he
scored 58 on a mathematics exam with a mean of 60 and a standard deviation of 5. Which of these
exam scores has a better position?
a) mathematics exam is better
b) no difference between both exams
c) arabic exam is better
d) none of the above
>>> من قاعدة z score ..
في العربي بيطلع -1
وفي الماث -.4
وطبعا واضح الدرجه الافضل في الماث