TEST 1									
							Measures of central tendency		
1) Determine the following values:							Mean:		
	10	20	25	30					
	10	20	25	30			Mode:		
	10	20	25	30					
	10	20	25	30			Median:		
	10	20	25	30					
	10	20	25	30			Measures of variability		
	10	20	25	30			Sample variance		
	10	20	25	30					
	10	20	25	30			Sample Standard deviation		
	10	20	30	30					
	10	20	30	30			Range		
	10	20	30	30					
	10	20	30	30			Variation coefficient		
	10	20	30	30					
									
2) Determine the average number of computers in households:									
									
number of computers	0	1	2	3					
number of households	5	8	10	4					
									
									
3) How many ways can four students be selected from a group of 6 students?									
4) If each value from random sample were tripled then its variance is:	nine times higher comparing to original one	three times higher comparing to original one	twice higher comparing to original one	the same					
									
5) Complete the following rules:				ANSWER (choose a)b)c)d))					
"A)Addition Rule: P(A ∪ B) =…..., where A and B are events."			a) ... = P(A) ⋅ P(B)	A) 					
B)Complementary Rule: P(A') = ……... denotes the probability of an event not happening.			b) ... = P(A) + P(B) - P(A∩B)	B)					
C)Independent events: P(A∩B) = …………			c) … = 1 - P(A). P(A')	C)					
D)Conditional probability: P(A | B) = ………..			d) … = P(A∩B) / P(B)	D)					
									
									
6) There are 6 green 8 red balls. Two balls are selected one by one without replacement. Find the probability that first is green and second is red.									
									
7) What is the probability of getting a sum of 10 when two dice are thrown?									
									
8)									
The number of days on business trip	Probability								
0	0.1								
1	0.4								
2	0.2								
3									
4	0.1								
									
"Fill in the missing value. Calculate mean, variance, mode, median."									
E(X)=									
									
9)  The probability of success (hitting the basket) is 0.9. We have 7 attempts.									
What is the probability of hitting the basket:									
a) just 4x?									
									
									
b) maxium 4x?									
									
									
c) less than 2x?									
									
E(X)=									
D(X)=									
									
10) The number of telephone connections to the rescue system is an average of 6 calls per 20 minutes.									
a) What is the probability that the system receives 10 calls in 30 minutes?									
									
									
									
b) no more than 8 calls per hour?									
									
									
c) at least 1 call per 40 minutes?									
									
									
E(X)=									
D(X)=