Statistics URT Statistics URT Statistics URT

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1. Statistics URT

2. c

3. b

4. Answer : B

5. If the slope of regreesion line y on x is -0.42 and the correlation coefficient between x and y is -0.89 then the slope Of regreesion line x on y B=r* Sy / Sx so Sy / Sx =0.472 So Sx / Sy =2.12 The slope of x on y=-0.89*2.12=-1.89 A

6. The tallest one(1) should be the mode Because it is the value the repeated much 3 will be mean and 2 will be median as in skewed right Mean>median, and its inverse in skewed left b

7. A Because the slope between any 2 points Is constant -1

8. Average is the mean Remark 3 in stem and no thing in the leaf I will not Count it and consider it does not exist , as it should be number in stem and number in leaf c

9. B

10. We will substitute by this number to get standard deviation of x and y and get the slope And from the law B=r* sy / sx we will get correlation coefficient that will be -1 perfect inverse correlation c

11. A

12. As mode=3*median-2*mean So median=14 As r=3*(mean-median)/standard deviation, so r=+0.97 positively skewed (right skewed) as mean>median D

13. b

14. a

15. Remark that is x on y -4.51 b

16. b

17. A

18. After getting mean of first numbers it will be 82-x=mean we will try from 80 to 85 and get value of x And substitute by value of x in means of second numbers that it will be 72-x after we substitute by value of x in each time the only number is produced And is in choices is 77

19. No thing happens, because of increasing in numbers, increasing value of mean and Difference between them will be the same before increasing, so standard deviations Does not change