Pre-Test Exam-2022_Statistics_CQ_EV_Sample Questions
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Subject Code: 1 2 9
BAF Shaheen College Dhaka Pre-Test -22 Creative Question Subject: Statistics Time-2 hours 35 minutes Full marks-50 [Answer any five questions in total taking at least two questions from each group] Group-A 1. Obtained marks in a class test of some students out of 25 marks are given:- 5, 8, 11, 14, 17, 20, 23, 26
(a) What is variable?1 (b) Explain and distinguish between discrete and continuous variable.2 (c) Using the data from the stem find the value of ∑8𝑖=1(𝑥𝑖 − 7)23 (d) Test and comment on the effect of origin and scale from the stem.4 2. A shrimp farmer showed the weight of produced shrimp in his firm as follows: Weight of shrimp (gram) 10-20 20-30 30-40 40-50 50-60 No of shrimp 7 10 18 6 5 (a) What is central tendency ?1 (b) Arihmetic mean is affected by extreme value- Explain.2 (c) From the stem find median.3 (d) Explain the relationship between AM and HM from the stem.4 3. Rasel is a student of business studies of class XII in a college. He collected weight of students of science and business studies group and analyze that the average weight of 20 students of business studies group is 55 kg. But the weight of a student of business studies group was written 25 instead of 52. The average weight of 24 students of science group is 58 kg. There is no mistake in this case. (a) What is called arithmetic mean ?1 (b) “arithmetic mean cannot be determined for open class interval”- Explain.2 (c) Find the actual average weight for the students of business studies group.3 (d) Determine the combined arithmetic mean of the students of two groups and comment.4 4. The first four moments of a distribution about the value 5 are 2, 20, 40 and 50 respectively. Mukit said that the distribution is positively skewed and leptokurtic. (a) What is moment ? 1
(b) Can the 2nd central moment be negative? - Explain 2
(c) Determine the standard deviation of the above stem. 3
(d) Are you agree with Mukit. Give your opinion after analyzing. 4
Group-B 5. A and B are two event where P(A) = 1 2 and P(B) = 1 5 and P(A∪B) = 5 8 . A teacher said that the value of P(A/B) and P(B/A) are not equal. (a) What is complementary event? 1
(b) The probability of the event ‘A’ is 0.83. What type of event is ‘A’ ? Explain. 2
(c) Find the value of P(A ∩ B) in light of stem. 3
(d) Find the value of P(A/B) and P(B/A) in light of stem and evaluate the accuracy of the teacher’s comment. 4
Pre-Test Exam-2022_Statistics_CQ_EV_Sample Questions
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6. Stem-1: Rakib throws 3 coins at a time. He wins 40 points for at least 1 Head but losses 20 points for at best 1 head. Rakib expects 45 points.
Stem-2: The probability functions of the number of wickets of a bowler in BPL cricket match is P(x)=|2−𝑥|
𝑘 ; x=3, 4, 5, 6, 7,.
(a) What is variance of random variable ? 1
(b) Explain that, V(6)=0 2
(c) Determine the value of k and E(X) from stem-2 3
(d) Justify the expectation of Rakib from stem-1 4
7. Roni draws 3 balls randomly from a box containing 7 white, 5 black and 3 red balls. He assumes that the events of getting at least 2 black balls and getting at best 1 black balls are complemantary. (a) Define mutually exclusive events. 1
(b) Mathematical expectation of random variable and arithmetic mean are basically same - explain. 2
(c) Determine the probability that the three balls drawn by Roni will be different colours. 3
(d) Give your opinion determining the probability whether the assumptions of Roni is true. 4
8. The probability distributions of demand of of mobile sets of two companies ‘Nokia’ and ‘Symphony ‘in a shop are as follows: Nokia Demand 0 1 2 3 4 Probability 0.1 0.4 C 0.15 0.1 Symphony Demand 0 1 2 3 4 Probability 0.09 0.45 0.32 0.11 0.03 (a) What is probability distribution? 1
(b) Can the standard deviation of a random variable be negative? Explain. 2
(c) Find the value of the constant C for Nokia mobile. 3
(d) Give your comment determining necessary measure which company’s mobile set has higher demand. 4
