B.C.A SEM1 - STATISTICS-OCT-2019

SAINTGITS COLLEGE OF APPLIED SCIENCES

SECOND INTERNAL ASSESSMENT EXAMINATION, OCTOBER 2019

Department of B.C.A, Semester I  Answer key

BASIC STATISTICS AND INTRODUCTORY PROBABILITY TYHEORY

Total   : 80 marks                                                                        Time:3Hours

Section A

1)    Statistics should be an aggregate of facts, numerically expressed, collected in a systematic manner.

2)    Census method-more Time consuming, Money ,Effort

Sample survey method-less money, Time ,Effort

3)    Explain stem and leaf chart

4)    Relationship between 2 or more variables

5)    bxy=-2/3

6)    P.E=0.08,S.E=0.05

7)    Graphical representation of correlation

8)    Collection of all sample spaces=  HH,HT,TH,TT

9)    Probability lies between 0 and 1,P(S)=1,P(AUB)=P(A)+P(B)

10)  Let A be an event, B1,B2,….Bn are Mutually exclusive events to happen that event then P(Bk/A)= p(Bk)P(A/Bk)/P(B1)P(A/B1)+………….

11)  Sum of probability=1, all f(x) is positive

12)  E(X)=Sum of ,Xp(x)

Section B

13)   Correlation is the degree of relationship, regression is the nature of relationship, Correlation is not for prediction but regression is the purpose for prediction.

14)   Mean=9, S.D=3.16

15)  Correlation=r=0.87

16)  byx=1.5,   Mean of x=4, Mean of y=5.8,  y=1.5x-0.2

17)  If A and B are two independent events, P(AUB)=p(A)+p(B), Apply Addition theorem of set theory

18)  4/6x3/8+2/6x5/8=22/48

19)  k=3, p(1<x<3) =p(x=1) +p(x=2) +p(x=3)1/2+3/10+1/30=5/6

20)  E(x)=1/2, e(x²) = 6/20=3/10,Variance=0.05

21)  P(B2/A)=  0.28/0.52=0.54

section c

22)  Mean=33.71, Median=33.5, Mode=33.85

23)  Mean value of x=13,   Mean value of y=17

2) Correlation=0.6   Standard Deviation of y=4

     24)  k=5/9,   Mean=69/54, =1.28,  V(x)=0.788

     25)   Missing frequencies are 23 and 21