Tribhuvan University
Bachelor of Information Technology
Semester 2 · TU Board 2080
Course Title: Basic Statistics (STA154)
Full Marks: 60Pass Marks: 24Time: 3 hours
Candidates are required to give their answers in their own words as far as practicable.
Group A
Attempt any Two questions.(2 × 10 = 20)
- 1.10
Distinguish between descriptive and inferential statistics. The following table represents the mark obtained by a batch of 10 students in a certain class tests in Basic Statistics and Computer science. Marks in Basic Statistics53555232306047463558Marks in Computer science57452431258443803272 Indicate in which subject is the level of more consistency?
- 2.10
Define regression. From the following table, compute the line of regression for estimating blood pressure: Blood pressure Y147125160118149128Age in years X564272366347 (i) Fit a regression equation that best describe the above data. (ii) Estimate the blood pressure when age is 50 yrs. (iii) Interpret the regression coefficient.
- 3.10
Under which situation Normal distribution will be used. The annual salaries of employees in a large company are approximately normally distributed with a mean of $50,000 and a standard deviation of $20,000. (a) What is the probability of people earns less than $40,000? (b) What is the probability of people earns between $45,000 and $65,000? (c) What is the probability of people earns more than $70,000?
Group B
Attempt any Eight questions(8 × 5 = 40)
- 4.5
Describe the role of Statistics in information technology.
- 5.5
The following table shows the mode of transport used by 400 students of a school. Represent the following information on the bar diagram and Pareto diagram. Mode of transportBusBicycleOn footBy carNo. of students2001008020
- 6.5
Write properties of correlation. A study is made relating aptitude scores to productivity in a factory after six months training of personnel. The following are the figures regarding six randomly selected workers: Aptitude Scores X: 9 18 18 20 20 23 Productivity Index Y: 12 33 23 42 29 30 Find the coefficients of correlation between aptitude score and productivity index and comment on the value. Also find coefficient of variation for each variable.
- 7.5
Define random variable. A random variable X has following probability functions. X012345P(X)0.1C0.22C0.3C Find, (i) The value of C. (ii) , . (iii) Mean and variance.
- 8.5
Define binomial distribution. Fit a binomial distribution on the following data: x01234f286246104
- 9.5
The probability that an integrated circuit chip will have defective etching is 0.12, the probability that it will have a crack defect is 0.29, and the probability that it has both defects is 0.07. What is the probability that a newly manufactured chip will have either an etching or crack defect.
- 10.5
If the first four moments about mean are 0, 2.8, -2 and 24.5 respectively. Compute coefficient of skewness and kurtosis and comment upon result.
- 11.5
The fuel consumption of a new model of cars is being tested. In one trial, 50 cars chosen at random were driven under the identical conditions and the distances, x km. covered on 1 liter of petrol were recorded. The results gave the following totals: € x=525, € x ^2=5625 . Calculate the 99% confidence interval for the mean petrol consumption, in km per liter. Interpret the result.
- 12.5
Write short note on the following: a) Use of Box and whisker plot. b) Parameter and Statistic.
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