Statistics and Probability Answers

1 A certain shop repairs both audio and video components. Let A denote the event that the next component brought in for repair is an audio component, and let B be the event that the next component is a compact disc player (so the event B is contained in A). Suppose that P(A)= 0.6 and P(B) =0.05. What is P(B|A)?
0.027
0.064
0.072
0.083

2 Components of a certain type are shipped to a supplier in batches of ten. Suppose that 50% of all such batches contain no defective components. 30% contain one defective component, and 20% contain two defective components. Two components from a batch are randomly selected and tested. What are the probabilities associated with 0.1, and 2 defective components being in the batch under the condition that neither tested component is defective.
0.677
0.512
0.578
0.617

At a party, you and your friend are both eying the last slice of pizza. To settle the matter, you agree on the following dice game: each of you is going to roll a die; if the highest number rolled by either one of you is a 1, 2, 3 or 4, then Player 1 wins. If the highest number is a 5 or a 6, then Player 2 wins. Assuming that you really want that last slice of pizza would you rather be Player 1 or Player 2 to maximize your chance of winning? Explain your choice.

A survey of 500 construction companies showed that 310 of them advertised in magazine A, 304 advertised in magazine B, and 220 advertised in both.

What is the probability that a construction company advertised in at least one of the two magazines?

if an additional data value that is far below the rest of the data is added to a data set, then the standard deviation will be increased.

Classify each of the following qualitative variables as ordinal or nominative. Explain
your answers.
Qualitative Variable
Personal computer operating system

6 Find the mode of 3,6,10,13, 14,17,19 and 22
20
17
20
13
7 Find the median of 3,19, 6,17,10,13, 14, and 22
13
20
17
13.5
8 calculate the arithmetic mean of 3,6,10,13, 14,17,19 and 22
20
15
13
17
9 The mean of four numbers is 5 and the mean deviation is 3. Find the fourth number if the mean deviation of the first three numbers is 2.
12
20
11
15
10 From the set A={3,
2√,23√,9√,7√
2,23,9,7
},a number is selected at random. Find the probability that is a rational number.

25
25

35
35
3
4

1 A die has four of its faces coloured white and the remaining two coloured black. What is the probability that when the die is thrown two consecutive times, the top face will be white in both cases ?

13
13

49
49

920
920

13
13
2 Three balls are drawn from a box containing 6 red marbles, 4 white marbles and 5 blue marbles. Find the probability that they are drawn in the order: red, white, and blue if each ball is drawn with replacement

2225
2225

1225
1225

4225
4225

8225
8225
3 When a die is thrown, what is the probability that the number is greater than 1, given that it is odd?

23
23

35
35

45
45

13
13
4 Giving that mean=34, median= 32 and standard deviation as 12. Calculate the Pearson's coefficient of skewness
0.5
0.4
0.3
1.6
5 Calculate the standard deviation of the marks: 2,3,6,2,5,0,4,2.
1.5
1.7
1.8
1.9

5 The probabilities of a boy passing English and Mathematics tests are a and b respectively. Find the probability of the boy failing both tests.
1-(a+b)+ab
1-(a+b)-ab
1-(a+b)
1-(a-b)-ab
6 Statistics is a descriptive measurement obtained from a ----------------
observation
sample
experiment
population
7 The grade of student on six examinations were 84, 91, 72, 68, 87, and 78. What is the arithmetic mean of the grades?
88
60
70
80
8 The scores of 5 students in an examination are: 6, 5, 8, 7 and 4. Find the variance.
3
2
2.5
4.5
9 The scientific method for collection, summarization, presentation, analysis and interpretation of data is called
statistics
investigation
biostatistics
questionairing
10 A ............. is the total collection of all the possible outcomes of an experiment
Sample space
Sample
Experiment
Statistics

1) The mean and the range of the sets of numbers 1.20, 1.00, 0.90, 1.40, 0.80, 0.80, 1.20 and 1.10 are m and r respectively. Find m - r.
a)1.69
b)0.45
c)1.67
d)1.16
2) Seven Matrons assembled for a meeting, shake hands with one another. How many handshakes take place … … … … … ….?
a)394
b)5040
c)124
d)490
3) What is the evaluation of 5! ?
a)120
b)140
c)110
d)112
4) If four coins are flipped in succession, then the number of possible outcomes is … … … … ….
a)8
b)12
c)16
d)14

25 students of your school participated in a tournament of three games namely : cricket, Football and
basket ball. 15 students received medals in cricket, 12 in Football, 11 in basketball, 5 in cricket and
basket ball, 9 in cricket and football, 4 in football and basketball and 3 in all the three games. How many
students received medals in (i) none of the games (ii) cricket only.