TN 12th Model Question Paper Statistics

No. of Printed Pages : 12
1369 (NP)
!1369NPStatistics! £vÄ Gs
Register Number

PART - III
¦Òΰ¯À / STATISTICS
( uªÌ ©ØÖ® B[Q» ÁÈ / Tamil & English Version)

Põ» AÍÄ : 2.30 ©o ÷|µ® ] [ ö©õzu ©v¨ö£sPÒ : 70
Time Allowed : 2.30 Hours ] [Maximum Marks : 70

AÔÄøµPÒ : (1) AøÚzx ÂÚõUPЮ \›¯õP £vÁõQ EÒÍuõ GߣuøÚ
\›£õºzxU öPõÒÍÄ®. Aa_¨£vÂÀ SøÓ°¸¨¤ß AøÓU
PsPõo¨£õÍ›h® EhÚi¯õPz öu›ÂUPÄ®.
(2) }»® AÀ»x P¸¨¦ ø©°øÚ ©mk÷© GÊxÁuØS®
AiU÷PõikÁuØS® £¯ß£kzu ÷Ásk®. £h[PÒ ÁøµÁuØS
ö£ß]À £¯ß£kzuÄ®.

Instructions : (1) Check the question paper for fairness of printing. If there is any lack of
fairness, inform the Hall Supervisor immediately.
(2) Use Blue or Black ink to write and underline and pencil to draw diagrams.

£Sv & I / PART - I

SÔ¨¦ : (i) AøÚzx ÂÚõUPÐUS® Âøh¯ÎUPÄ®. 15x1=15

(ii) öPõkUP¨£mkÒÍ ©õØÖ ÂøhPÎÀ ªPÄ® Hئøh¯
Âøhø¯z ÷uº¢öukzxU SÔ±mkhß Âøh°øÚ²® ÷\ºzx
GÊuÄ®.
Note : (i) Answer all the questions.
(ii) Choose the most appropriate answer from the given four alternatives and
write the option code and the corresponding answer.

[ v¸¨¦P / Turn over

1369 (NP) 2

1. |ßS S¾UP¨£mh J¸ ^mkUPmi¼¸¢x J¸ "ì÷£m' µõo ö£ÖÁuØPõÚ
{PÌuPÄ :
4 1 1
(A) 13 (B) 1 (C) 13 (D) 52
Probability of drawing a spade queen from a well shuffled pack of cards is :

4 1 1
(a) (b) 1 (c) (d)
13 13 52

2. P(X)=0.15, P(Y)=0.25, P(X Y)=0.10 GÛÀ P(X Y) &Cß ©v¨¦ :

(A) 0.30 (B) 0.40 (C) 0.10 (D) 0.20
P(X)=0.15, P(Y)=0.25, P(X Y)=0.10 then P(X Y) is :
(a) 0.30 (b) 0.40 (c) 0.10 (d) 0.20

3. E(2X+3) Gߣx :

(A) E(3) (B) 2X+3 (C) E(2X) (D) 2E(X)+3
E(2X+3) is :
(a) E(3) (b) 2X+3 (c) E(2X) (d) 2E(X)+3

∫ e dx=
x
4.

(A) 2ex+c (B) x+c (C) ex+c (D) e−x+c

∫ e dx=
x

(a) 2e x+c (b) x+c (c) ex+c (d) e−x+c

5. D¸Ö¨¦¨£µÁ¼ß ©õÖ£õk 2 GÛÀ, Auß vmh»UP® :

(A) 1 2 (B) 2 (C) 2 (D) 4
If the variance of a binomial distribution is 2, then its standard deviation is :

(a) 1 (b) (c) 2 (d) 4
2 2

3 1369 (NP)

6. wºÄ Pmh £Sv Gߣx :
(A) {PÌuPÄ (B) ÷\õuøÚ¨ ¦Òΰ¯À ©v¨¦
(C) ©ÖUS® £Sv (D) HØS® £Sv
Critical region is :
(a) Probability (b) Test Statistic Value
(c) Rejection Area (d) Acceptance Area

7. øPÁºUP ÷\õuøÚ°À 5×4 ÷uºÄ¨£mi¯¼ß Áøµ¯ØÓ £õøP :
(A) 14 (B) 10 (C) 20 (D) 12
Degrees of freedom for Chi-square in case of contingency table of order (5×4) are :
(a) 14 (b) 10 (c) 20 (d) 12

8. Cµsk \µõ\›PÐUS Cøh÷¯¯õÚ Âzv¯õ\zvØPõÚ ¦Òΰ¯À
÷\õuøÚ¯õÚx :
x 1−x 2 p1−p 2 p−P
(A) σ 12 σ 22 (B)  1 1  (C)
x− µ
(D) PQ
+ PQ  +  σ/ n
n1 n2  n1 n 2  n
Test statistic for difference between two means is :

x 1−x 2 p1−p 2 p−P
(a) σ 12 σ 22 (b)  1 1  x− µ
PQ
+ PQ  +  (c) σ/ n
(d)
n1 n2  n1 n 2  n

9. ìlhsm t &£µÁ¼ß •ß÷Úõi :
(A) R.A. ¤åº (B) ÂÀ¼¯® S. Põöém
(C) PõºÀ ¤¯ºéß (D) »õ¨»õì
Student’s ‘t’ distribution was pioneered by :
(a) R.A. Fisher (b) William S. Gosset
(c) Karl Pearson (d) Laplace

10. TSS, SSR ©ØÖ® SSC •øÓ÷¯ 90, 35, 25 öPõsh C¸ÁÈ £õS£õmiÀ SSE
BÚx:
(A) 30 (B) 20 (C) 50 (D) 40
With 90, 35, 25 as TSS, SSR and SSC respectively in case of two way classification, SSE
is :
(a) 30 (b) 20 (c) 50 (d) 40

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1369 (NP) 4

11. Põ»z öuõhº Á›ø\°À EÒÍ ¤›ÄPÎß GsoUøP :
(A) |õßS (B) I¢x
(C) Cµsk (D) ‰ßÖ
A time series consists of :
(a) Four components (b) Five components
(c) Two components (d) Three components
12. J¸ Põ»z öuõhº Á›ø\°À Põn¨£k® Põ»õsk HØÓ CÓUP[PøÍ öu›Ä
ö\´Áx __________ ©õÖ£õk BS®.
(A) JÊ[PØÓ (B) }shPõ» (C) £¸ÁPõ» (D) _ÇÀ
Quarterly fluctuations observed in a time series represent __________ variation.
(a) Irregular (b) Long-term (c) Seasonal (d) Cyclical
13. A, B GßÓ C¸ £s¦PÐUS (AB)=0 GÛÀ, Q &ß ©v¨¦ :
(A) 0 (B) −1 ≤ Q ≤ 1 (C) 1 (D) −1
In case of two attributes A and B the class frequency (AB)=0, the value of Q is :
(a) 0 (b) −1 ≤ Q ≤ 1 (c) 1 (d) −1
14. Q=+1 GÛÀ A, B &UQøh÷¯ EÒÍ EÓÄ :
(A) •Êø©¯õÚ ÷|›øh EÓÄ
(B) •Êø©¯õÚ Gv›øh EÓÄ
(C) EÓÄ CÀø»
(D) ÷©ØTÔ¯ AøÚzx®
If Q=+1, then the association between A and B is :
(a) Perfect positive association
(b) Perfect negative association
(c) No association
(d) All the above
15. CÆÁÍøÁø¯U öPõsk «¨ö£¸ AÎzuÀ SøÓÁõP C¸UøP°À
ö\¯Ø£õmøh ÷uºÄ ö\´Áx :
(A) «a]ÖÂß «¨ö£¸ AÍøÁ
(B) «¨ö£¸Âß «a]Ö AÍøÁ
(C) «¨ö£¸Âß «¨ö£¸ AÍøÁ
(D) CÁØÔÀ JßÖªÀø»
The Criterion which selects the action for which maximum Pay-off is lowest is known
as :
(a) Max-Min criterion
(b) Min-Max criterion
(c) Max-Max criterion
(d) None of these

5 1369 (NP)

£Sv & II / PART - II

H÷uÝ® BÖ ÂÚõUPÐUS Âøh¯ÎUPÄ®. 24 &Áx ÂÚõÄUS
Pmhõ¯©õP Âøh¯ÎUPÄ®. 6x2=12
Answer any six of the following. Question no. 24 is compulsory.
16. {PÌuPÄ ÷Põm£õkPøÍU TÖP.
State the axioms of Probability.

17. wº©õÚ ©µ ÁiÁzvß £¯ß£õkPÒ CµsiøÚU TÖP.
Give any two advantages of decision tree.

18. D¸Ö¨¦¨£µÁ¼ß \µõ\› ©ØÖ® vmh»UP® •øÓ÷¯ 10 ©ØÖ® 2 GÛÀ,
n ©ØÖ® p &ß ©v¨¦PøÍU PõsP.
In a binomial distribution, the mean and standard deviation are 10 and 2 respectively.
Find n and p.

19. ]Ó¨¦U Põs ©mh® £ØÔ }º AÔÁx ¯õx ?
What do you mean by level of Significance ?

20. C¸ ÂQu \© Âzv¯õ\[PÎß ©õÖ£õmøh GÊxP.
Write the variance of difference between two proportions.

21. t &£µÁ¼ß £s¦PÎÀ H÷uÝ® Cµsøhz u¸P.
State any two properties of t-distribution.

22. _ÇÀ ©õÖ£õk GßÓõÀ GßÚ ?
What is Cyclic Variation ?

23. ³¼ß öuõhº¦U öPÊøÁU TÖP.
Give Yule’s coefficient of association.

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1369 (NP) 6

5x 2 +x
24. ©v¨¦U PõsP : Limit
x →1 x+2

5x 2 +x
Evaluate Limit
x →1 x+2

£Sv & III / PART - III

H÷uÝ® BÖ ÂÚõUPÐUS Âøh¯ÎUPÄ®. AvÀ 33 &Áx ÂÚõÂØS
Psi¨£õP Âøh¯ÎUPÄ®. 6x3=18

Answer any six of the following. Question no. 33 is compulsory. .

25. J¸ ö£mi°À 4 P¸¨¦ {Ó¨£¢xPЮ, 6 öÁÒøÍ {Ó¨£¢xPЮ EÒÍÚ.
3 £¢xPÒ \©Áõ´¨¦ •øÓ°À GkUP¨£mhõÀ

(i) GÀ»õ® P¸¨¦ {Ó©õP (ii) GÀ»õ® öÁÒøÍ {Ó©õP C¸UP ÷Ási¯
{PÌuPøÁU PõsP.

A box contains 4 black balls and 6 white balls. If 3 balls are drawn at random, find the
probability that (i) all are black (ii) all are white.

26. J¸ öuõhº \©Áõ´¨¦ ©õÔ X, ¤ßÁ¸® Ahºzva \õºø£U öPõsi¸UQÓx,
Ax f(x)=Ax3, 0<x<1 GÛÀ A &ß ©v¨ø£U Psk¤iUPÄ®.

A continuous random variable X follows the probability law. f(x)=Ax 3, 0<x<1
determine the value of A.

7 1369 (NP)

27. (i) «a]ÖÂß «¨ö£¸
(ii) «¨ö£¸Âß «a]Ö CǨø£ £¯ß£kzv RÌUPsh AÎzuÀ Ao°À
{PÌuPøÁ¨ £ØÔ öu›¯õu {ø»°À G¢u wº©õÚzøu £›¢xøµ
ö\´Áõ´ ?
`Ì{ø» {ø»¨£õk
ö\¯À S1 S2 S3
a1 14 8 10
a2 11 10 7
a3 9 12 13
Apply (i) Maximin (ii) Minimax regret to the following pay-off matrix to recommend
the decisions without any knowledge of Probability :
States of nature

Act S1 S2 S3
a1 14 8 10
a2 11 10 7
a3 9 12 13

28. •uÀ ÁøP¨¤øÇ ©ØÖ® Cµshõ® ÁøP¨¤øÇ CÁØøÓ öuÎÁõP
ÂÁ›UPÄ®.
Explain clearly type I and type II errors.

29. 400 ©õv›PÎß Tmk \µõ\› 99. C¢u ©õv› Tmk \µõ\› 100 ©ØÖ® ©õÖ£õk
64 EÒÍ C¯À{ø» •Êø©z öuõSv°¼¸¢x GkUP¨£mhuõ GÚ 5%
]Ó¨¦Põs ©mhzvß ‰»® ÷\õuøÚ ö\´P.
A sample of size 400 was drawn and the sample mean was found to be 99. Test
whether this sample could have come from a normal population with mean 100 and
variance 64 at 5% level of significance.

30. ÁÇUP©õÚ SÔ±kPÎÀ R÷Ç öPõkUP¨£mkÒÍ ÂÁµ[PÎß
ö£õ¸zu•øhø©ø¯ Bµõ´P.
N=500, (A)=100, (B)=150, (AB)=60.
Test the consistency of the following data with the symbols having their usual meaning
N=500, (A)=100, (B)=150, (AB)=60.

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1369 (NP) 8

31. ¤ßÁ¸® ÂÁµ[PÐUS 3 Á¸h[PÐUPõÚ |P¸® \µõ\› PnUQkP.

Á¸h® 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984

EØ£zv
50 36 43 45 39 38 33 42 41 34
(hßPÎÀ)

Calculate the three yearly moving average of the following data :

Year 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984

Production
50 36 43 45 39 38 33 42 41 34
in (tonnes)

32. RÌUPsh ÂÁµ[Pμ¸¢x A, B GßÓ £s¦PÒ \õº£ØÓøÁ¯õ AÀ»x
÷|›øhz öuõhº¦øh¯øÁ¯õ AÀ»x Gv›øhz öuõhº¦øh¯øÁ¯õ GÚU
PõsP.

(AB)=64, (αB)=192, (Aβ)=12, (αβ)=36.

Show that whether A and B are independent, positively associated (or) negatively
associated.

(AB)=64, (αB)=192, (Aβ)=12, (αβ)=36.

33. J¸ £õ´éõß £µÁ¼À P(X=2)=P(X=3) GÛÀ, P(X=5)&I PõsP. [e−3=0.050]

In a Poisson distribution if P(X=2)=P(X=3), find P(X=5) [given e−3=0.050]

9 1369 (NP)

£Sv & IV / PART - IV

AøÚzx ÂÚõÂØS® Âøh¯ÎUPÄ®. 5x5=25

Answer the following.

34. (A) v¸S BoPÒ u¯õ›US® J¸ öuõÈØ\õø»°À, Auß ö©õzu
EØ£zv°À, A[SÒÍ A1, A2, A3 GßÓ ‰ßÖ G¢vµ[PÒ •øÓ÷¯ 25%,
35% ©ØÖ® 40% u¯õ›US® vÓÝøh¯øÁ. u¯õ›UP¨£mh v¸S
BoPÐÒ 5%, 4%, 2% v¸S BoPÒ SøÓ£õkÒÍøÁ. J¸ v¸S
Bo \©Áõ´¨¦ •øÓ°À ÷uº¢öukUP¨£mk Ax SøÓ£õkÒÍx
GßÖ PshÔ¯¨£kQÓx. Ax A2 GßÓ G¢vµz u¯õ›¨¤À C¸¢x
Á¸ÁuØPõÚ {PÌuPÄ GßÚ ?
AÀ»x
(B) J¸ \©Áõ´¨¦ ©õÔ X ¤ßÁ¸® {PÌuPĨ£µÁø»¨ ö£ØÔ¸UQÓx.

X −1 0 1 2
1 1 1 1
P(X)
3 6 6 3

E(X), E(X2), Var(X) BQ¯ÁØøÓU PõsP.

(a) In a bolt factory, Machines A 1 , A 2 , A 3 manufacture 25%, 35% and 40%
respectively of the total output. Of these 5, 4 and 2 percent are defective bolts.
A bolt is drawn at random from the product and is found to be defective. What
is the probability that it was manufactured by Machine A2 ?

OR

(b) A random variable X has the following distribution.

X −1 0 1 2
1 1 1 1
P(X)
3 6 6 3

Find E(X), E(X2) and Var(X).

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1369 (NP) 10

35. (A) J¸ C¯À{ø»¨ £µÁ¼À 20% EÖ¨¦PÒ 100 &US SøÓÁõPÄ®, 30%
EÖ¨¦PÒ 200 &US® ÷©÷» EÒÍx GÛÀ A¨£µÁ¼ß \µõ\› ©ØÖ®
vmh»UPzøu PõsP.

AÀ»x

(B) J¸ PÀ¿›°À £°¾® 800 ©õnÁºPÒ, AÁºPÎß ~snÔÄ ©ØÖ®
Ãmiß ö£õ¸Íõuõµ {ø»ø¯ øÁzx uµ® ¤›UP¨£kQßÓÚº.
χ 2 ÷\õuøÚø¯¨ £¯ß£kzv Ãmiß ö£õ¸Íõuõµ {ø»US®
~snÔÂØS® öuõhº¦ C¸UQÓuõ GÚU PõsP.

ö£õ¸Íõuõµ {ø» ~snÔÄ ö©õzu®

AvP® SøÓÄ

£nUPõµº 200 300 500

HøÇ 140 160 300

ö©õzu® 340 460 800

(a) In a normal distribution 20% of the items are less than 100 and 30% are over 200.
Find the Mean and Standard deviation of the distribution.

OR

(b) 800 students at college level were graded according to their IQ and the economic
conditions of their homes. Use χ2 test to find out whether there is any association
between economic condition at home and IQ.

Economic conditions IQ Total

High Low

Rich 200 300 500

Poor 140 160 300

Total 340 460 800

11 1369 (NP)

36. (A) J¸•øÚ ©ØÖ® C¸•øÚ ÷\õuøÚPøͨ £ØÔ Â›ÁõÚ Âøhz
u¸P.
AÀ»x
(B) R÷Ç öPõkUP¨£mh ÂÁµ[PÐUS Gί \µõ\› •øÓ°À £¸ÁPõ»
SÔ±kPÒ PõsP.
Põ»õsk
Á¸h® I II III IV
1989 30 40 36 34
1990 34 52 50 44
1991 40 58 54 48
1992 54 76 68 62
1993 80 92 86 82
(a) Write a detailed note on one-tailed and two-tailed tests.
OR
(b) Find the seasonal variations by simple average method for the data given below :
Quarter
Year I II III IV
1989 30 40 36 34
1990 34 52 50 44
1991 40 58 54 48
1992 54 76 68 62
1993 80 92 86 82

37. (A) R÷Ç öPõkUP¨£mkÒÍ GsPÒ 12 ¤›Ä {»[PÎÀ £°›h¨£mh A, B
©ØÖ® C ÁøP ÷Põxø©°ß EØ£zv AÍøÁ (Q÷»õ QµõªÀ)
SÔUQßÓÚ.
A : 20 18 19
B : 17 16 19 18
C : 20 21 20 19 18
‰ßÖ ÁøP ÷Põxø© EØ£zv AÍÂÀ HuõÁx ]Ó¨£õÚ Âzv¯õ\®
EÒÍuõ?
AÀ»x
(B) C¸ £õ»º £°¾® J¸ PÀ {ø»¯zvÀ £iUS® 200 ÷£ºPÎÀ
150 ÷£º ©õnÁºPÒ. AÁºPÎÀ 120 ÷£º ÷uºÂÀ ÷uºa] Aøh¢uÚº.
10 ©õnÂPÒ ÷uõÀ²ØÓÚº. ÷uºÂÀ öÁØÔ ö£ØÓø©US®
£õ¼ÚzvØS® Cøh÷¯ H÷uÝ® öuõhº¦ EÒÍuõ GÚ Bµõ´P.

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1369 (NP) 12

(a) The following figures relate to Production in kg of three varieties A, B and C of
wheat shown in 12 plots.
A : 20 18 19
B : 17 16 19 18
C : 20 21 20 19 18
Is there any significant difference in the Production of the three varieties ?
OR
(b) In a Co-educational Institution, out of 200 students, 150 were boys. They took
an examination and it was found that 120 passed, 10 girls failed. Is there any
association between sex and success in the examination ?

38. (A) J¸ P®ö£Û EØ£zv ö\´u 200 Jθ® JÎ ÂÍUSPÎß \µõ\›
B²mPõ»® 2670 ©o ÷|µ® ©ØÖ® Auß vmh »UP® 220 ©o ÷|µ®
BS®. A¢u P®ö£Û u¯õ›zu AøÚzx ÂÍUSPÎß \µõ\›
B²mPõ»® µ GÛÀ, Gk÷PõÒ µ=2700 ©o ÷|µ® Gߣøu AuØS
GvµõÚ ©õØÖ Gk÷PõÒ µ ≠ 2700 ©o ÷|µzvØS, 5% ]Ó¨¦ Põs
©mhzvÀ ÷\õuøÚ ö\´P.
AÀ»x
(B) ¤ßÁ¸® ÂÁµ[PÐUS «a]Ö ÁºUP •øÓ°À ÷£õUSU ÷Põmøh
ö£õ¸zxP.

Á¸h® : 2001 2002 2003 2004 2005 2006 2007

ÂØ£øÚ :
60 72 75 65 80 85 95
(»m\[PÎÀ)
(a) The mean lifetime of 200 fluorescent light bulbs produced by a company is
computed to be 2670 hours with a standard deviation of 220 hours. If µ is the
mean lifetime of all the bulbs produced by the company, test the hypothesis
µ=2700 hours against the alternative hypothesis µ ≠ 2700 hours using a 5% level
of significance.
OR
(b) Fit a straight line trend by the method of least square to the following data.

Year : 2001 2002 2003 2004 2005 2006 2007
Sales :
60 72 75 65 80 85 95
(in Lakhs)

-oOo-