Experiment

Q. Define an event.

Q. The probability of guessing a correct answer x/2 and not guessing an answer is 2/3 .Then find x

Q. Their are 100 bulbs in that 30 are detected find the probability

Q. The probability that a leap year selected at random will contain either 53 thursdays or 53 fridays is:

1. 5/7
2. 4/7
3. 3/7
4. 2/7

Q.

A lot of 20 bulbs contain 4 defective ones. One bulb is drawn at random from the lot.
What is the probability that this bulb is defective ?

1. 0.4

2. 0.2

3. 0.8

4. 0.6

Q.

There are $30$ boys and $25$ girls in a class. A student is chosen at random. Find the probability that the chosen student is a boy.

Q. Which of the following is the sample space when a coin is tossed twice?

1. {H, T, H, T}
2. {H, T}
3. {HH, HT, TH, TT}
4. {HH, TT}

Q. In a survey conducted recently with 100 families, the number of children in each family was recorded and tabulated as shown below:

Number of children	Families
0	40
1	30
2	40

How many families have atleast one child?

1. 50
2. 30
3. 70
4. 80

Q. What is the probability that a leap year when selected at random, contains 53 Sundays?

1. 2/7
2. 1/7
3. 4/7
4. 3/7

Q. If random error in an experiment for 30 observations is a then random error in the experiment for 120 observations will be

Q.

what is the probability of getting atmost 1 head if three coins are tossed togethe??.

(list the outcomes and also a the meaning of atmost)

Q. Do we have to learn both 9th and 10​​​​​th class probability or only 9th class probability

Q. A card is drawn from a pack of playing cards. The probability that the card drawn at random is either a queen or a king is

1. $\frac{3}{4}$
   
2. $\frac{1}{13}$
   
3. $\frac{2}{3}$
   
4. $\frac{2}{13}$
   

Q. From a deck of playing cards, if the cards which show the factors of 10 and red coloured face cards are removed from the deck, then the probability of selecting a black coloured face card is

1. $\frac{1}{17}$
   
2. $\frac{3}{17}$
   
3. $\frac{5}{17}$
   
4. $\frac{19}{34}$
   

Q. The probability of a man hitting a target is 1/4. If he fires 7 times, what is the probability of his hitting the target at least twice?

Q.

$5$ girls and $10$ boys sit at random in a row having $15$ chairs numbered as $1$ to $15$, then the probability that end seats are occupied by the girls and between any two girls and odd number of boy sit is $5\mathrm{K}*10!*5!/15!$. Find $\mathrm{K}$

Q. Following table shows the birth month of 40 students of class IX.

Jan.	Feb	March	April	May	June	July	Aug.	Sept.	Oct.	Nov.	Dec.
3	4	2	2	5	1	2	5	3	4	4	4

Find the probability that a student was born in August.

Q.

How do you know when to use a Poisson distribution or binomial distribution ?

Q.

In a survey of 364 children aged 2-4 years, it was found that 91 liked to eat potato chips. If a child is selected at random, the probability that he/she does not like to eat potato chips is:

1. 0.25

2. 0.50

3. 0.75

4. 0.80

Q. There are several human beings and several cows in a village. One tenth of the humans have lost a leg. The total number of feet is 77. If anyone is chosen at random from the village, then the probability of not getting a cow is

1. $\frac{1}{7}$
   
2. $\frac{3}{5}$
   
3. $\frac{5}{7}$
   
4. $\frac{6}{7}$
   

Q. In a class of 56 students, some students are boys and some are girls. If the probability of selecting a boy is the same as the probability of getting at least one tail when three coins are tossed simultaneously, then the number of girls in the class is

1. 47
2. 48
3. 7
4. 15

Q. To know the opinion of the students about Mathematics, a survey of 200 students was conducted. The data is recorded in the following table:

Opinion:	Like	Dislike
Number of students:	135	65

Find the probability that a student chosen at random (i) likes Mathematics (ii) does not like it.

Q. In an examination, out of 70 students some students pass in the examination and some students fail. If the probability of selecting a student who passed in the examination is 4 times the probability of selecting a student who failed in the examination, then the difference between the number of students who pass and the number of students who fail is

1. 14
2. 28
3. 42
4. 56

Q.

In a particular section of Class IX, $40$ students were asked about the months of their birth and the following graph was prepared for the data so obtained:

Find the probability that a student of the class was born in August.

Q. The histogram shows the age groups of working women in a city. Find the number of working women in the age group of $29-34$ years.

1. $300$
2. $410$
3. $230$
4. $320$

Q. if three coins are tossed simutaneously than find the probability of getting atleast two heads

Q. The table given below shows the month of birth of 36 students of a class.

Month of birth	Jan	Feb	Mar	Apr	May	June	July	Aug	Sept	Oct	Nov	Dec
No. of students	4	3	5	0	1	6	1	3	4	3	4	2

A student is chosen at random from the class. What is the probability that the chosen student was born in October?
(a) $\frac{1}{3}$

(b) $\frac{2}{3}$

(c) $\frac{1}{4}$

(d) $\frac{1}{12}$

Q.

The above table depicts the age group of people living in an apartment. Since the group width is unequal find the length of rectangle with respect to age group width 5 per interval.

$\begin{array}{cc}\text{age group}& \text{number of people}\\ 10-19& 12\\ 20-24& 13\\ 25-29& 36\\ 30-34& 15\end{array}$
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Q. A coin is tossed 40 times and the head appears 15 times what is the probability of getting a tail.

Q. A survey of 600 students on their preference for coffee was conducted and recorded as shown:

Opinion	Like	Dislike
No. of students	360	140

Out of these students one is chosen at random. What is the probability that the chosen student
(i) likes coffee?
(ii) dislikes coffee?