IUBAT窶的NTERNATIONAL UNIVERSITY OF BUSINESS AGRICULTURE AND TECHNOLOGY Final examination

STA 240

Full marks: 100

ID

Time: 3 hours

NAME

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1. What is the probability of choosing a consonant from the alphabet? 2. The observation which occurs most frequently in a sample is the ______ . 3. What is the median of the sample 5, 5, 11, 9, 8, 5, 8? 4. A graph that uses vertical bars to represent data is called a _______ . 5. As a general rule, the ______ is the best measure of central tendency. 6. The ______ is the value you calculate when you want the arithmetic average. 7. ____ are used when you want to visually examine the relationship between two quantitative variables. 8. The range of the correlation coefficient is _________ to

_________ .

9. For what value of x, will 8 and x have the same mean (average) as 27 and 5? 10. A disadvantage of the range is only _____ values are used in its calculation. 11. The mean deviation is based on ______ values. 12. The standard deviation is based on ______ deviations from the mean. 13. The standard deviation can never be _______ .

14. We can get variance by _______ standard deviation. 15. How many dependent variables are used in multiple regression models? 16. Y = 5 + 2X. Interpret α and β. 17. Find the two numbers whose HM=32/5 and GM=8. 18. Find CV of two numbers 5 and 3. 19. If SD of 1st n natural numbers is √10, what will be the mean? 20. Hospital records show that of patients suffering from a certain disease, 55% die of it. What is the probability that of 5 randomly selected patients, 3 will recover? 21. Interpret the following results : a) r = 0.79

b) r = 0.65

c) r = 0.34

d) r = 0.18

22. Find MD and SD of the numbers 0, 1, 2. 23. Construct a steam & leaf plot for the following data : 11,14,16,21,23,24,27,30,31,35,36,37,38,40,41,42,43,50,51 24. Two coins are tossed; find the probability that a) At most one tail is obtained. b) At least one head is obtained. 25. For any two numbers, GM=√7 and SD=3. Find (a) The numbers

(b) HM

(c) Variance

(d) AM

(e) Median

26. Find the mean for the series 1000, 2000, 3000, …………, 50000. 27. What is the sample space of choosing a vowel from the alphabet?

(f) CV.

28. A sample of 40 sales receipts from a grocery store has mean = $137 and SD = $30. Use these values to test whether or not the mean is sales at the grocery store are different from $150. 29. A company makes electric motors. The probability an electric motor is defective is 0.01. What is the probability that a sample of 200 electric motors will contain exactly 5 defective motors? 30. A jar contains 3 red marbles, 7 green marbles and 5 white marbles. If a marble is drawn from the jar at random, what is the probability that a) The marble is white? b) The marble is either white or red? 31. The number of persons X, in a family chosen at random has the following probability distribution:

X

1

2

3

4

P(X)

0.25

0.25

m

0.25

A) Find the value of m. B) Find the average family size E (X). C) Also find V(X).

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