Recent questions tagged sec-c

Find the equation of the circle passing through $(0,0)$ and making intercepts a and b on the coordinate axes.

asked Jul 13, 2014 by thanvigandhi_1

1 answer

The mean and standard deviation of a set of $n_1$ observations are $\bar{x_1}$ and $s_1$ respectively , while the mean and standard deviation of another set of $n_2$ observations are $x_2$ and $s_2$ respectively. Show that the standard deviation of the combined set of $(n_1+n_2)$ observations is given by $ S.D= \sqrt {\large\frac{n_1 (s_1)^2 +n_2 (s_2)^2}{n_1+n_2} +\frac{n_1n_2(\bar {x_1} -\bar {x_2} )^2}{(n_1+n_2)^2}}$

asked Jul 9, 2014 by meena.p

1 answer

Let $a,b,c,d,e$ be the observations with mean m and standard deviations $S$. The standard deviation of the observations $a+k,b+k,c+k,d+k,e+k$ is

asked Jul 8, 2014 by meena.p

1 answer

A sample space consists of a elementary outcomes $e_1,e_2........e_9$ whose probabilities are $P(e_1)=P(e_2)=0.08,P(e_3)=P(e_4)=P(e_5)=.1,P(e_6)=P(e_7)=.2,P(e_8)=p(e_9)=0.07$.Suppose $A=\{e_1,e_5,e_8\},B=\{e_2,e_5,e_8,e_9\}$.Using the addition law of probability ,calculate $P(A \cup B)$ .

asked Jul 8, 2014 by sreemathi.v

1 answer

A card is drawn from a deck of 52 cards.Find the probability of getting a king or a heart or a red card.

asked Jul 8, 2014 by sreemathi.v

1 answer

A bag contains 8 red and 5 white balls.Three balls are drawn at random.Find the probability that one ball is red and two balls are white

asked Jul 8, 2014 by sreemathi.v

1 answer

While calculating the mean and variance of $10$ readings, a student wrongly used the reading $52$ for the correct reading $25$, the obtained the mean and variance as $45$ and $16$ respectively . Find the correct mean and the variance.

asked Jul 7, 2014 by meena.p

1 answer

Mean and standard deviation of $100$ observation were found to be $40$ and $10$ respectively . If at the times of calculation two observations were wrongly takes as $30$ and $70$ in place of $3$ and $27$ respectively. Find the correct standard deviation.

asked Jul 7, 2014 by meena.p

1 answer

One of the four persons John,Rita,Aslam or Gurpreet will be promoted next month.Consequently the sample space consists of four elementary outcomes S={John promoted,Rita promoted,Aslam promted,Gurpreet promoted}.You are told that the chances of John's promotion is same as that of Gurpreet,Rita's chances of promotion are twice as likely as John's,Aslam's chances are four times that of John.If A ={John promoted or Gurpreer promoted} find P(A)

asked Jul 7, 2014 by sreemathi.v

1 answer

One of the four persons John,Rita,Aslam or Gurpreet will be promoted next month.Consequently the sample space consists of four elementary outcomes S={John promoted,Rita promoted,Aslam promted,Gurpreet promoted}.You are told that the chances of John's promotion is same as that of Gurpreet,Rita's chances of promotion are twice as likely as John's,Aslam's chances are four times that of John.Determine P(John promoted),P(Rita promoted),P(Aslam promoted),P(Gurpreet promoted)

asked Jul 7, 2014 by sreemathi.v

1 answer

Following are the marks obtained , out of 100 by two students Ravi and Hashina in 10 tests: Who is more intelligent and who is more consistent?

asked Jul 7, 2014 by meena.p

1 answer

A die is loaded in such a way that each odd number is twice as likely to occur as each even number.Find P(G),where G is the event that a number greater than 3 occurs on a single roll of the die.

asked Jul 7, 2014 by sreemathi.v

1 answer

Determine mean and standard deviation of first n terms of an A.P whose first term is 'a' and common difference d.

asked Jul 7, 2014 by meena.p

1 answer

Six new employees,two of whom are married to each other,are to be assigned six desks that are lined up in a row.If the assignment of employees to desks is made randomly,what is the probability that the married couple will have non adjacent desks?

asked Jul 7, 2014 by sreemathi.v

1 answer

Determine the mean and standard deviation for the following distribution:

asked Jul 4, 2014 by meena.p

1 answer

Calculate the mean deviation from the median of the following frequency data:

asked Jul 4, 2014 by meena.p

1 answer

Find the mean and variance of the frequency distribution given below:

asked Jul 4, 2014 by meena.p

1 answer

There are 60 students in a class .The following is the frequency distribution of the marks obtained by the students in a test : where x is a positive integer . Determine the mean and standard deviation of the marks.

asked Jul 3, 2014 by meena.p

1 answer

If four digit numbers greater than 5000 are randomly formed from the digits 0,1,3,5 and 7,what is the probability of forming number divisible by 5 when repetition of digits is not allowed.

asked Jul 3, 2014 by sreemathi.v

1 answer

If four digit numbers greater than 5000 are randomly formed from the digits 0,1,3,5 and 7,what is the probability of forming number divisible by 5 when the digits are repeated ?

asked Jul 3, 2014 by sreemathi.v

1 answer

From the employees of a company ,5 persons are selected to represent them in managing committee of the company.Particulars of five persons are as follows :

asked Jul 3, 2014 by sreemathi.v

1 answer

Find the equations of the lines through the point of intersection of the lines $x-y+1=0 $ and $ 2x-3y+5 = 0$ and whose distance from the point (3, 2) is $ \large\frac{7}{5}$

asked Jul 2, 2014 by thanvigandhi_1

1 answer

Three letters are dictated to three persons and an envelope is addressed to each of them,the letters are inserted into the envelopes at random so that each envelope contains exactly one letter.Find the probability that at least one letter is in its proper envelope.

asked Jul 2, 2014 by sreemathi.v

1 answer

Out of 100 students,two sections of 40 and 60 are formed.If you and your friend are among the 100 students,what is the probability that,you both enter the different sections?

asked Jul 2, 2014 by sreemathi.v

1 answer

The mean and standard deviation of marks obtained by 50 students of a class in three subjects , mathematics, physics and chemistry are given below:Which of these three subjects shows the highest variability in marks and shows the lowest?

asked Jul 2, 2014 by meena.p

1 answer

Out of 100 students,two sections of 40 and 60 are formed.If you and your friend are among the 100 students,what is the probability that,you both enter the same section

asked Jul 2, 2014 by sreemathi.v

1 answer

The mean and standard deviation of 20 observations are found to be 10 and 2 respectively. On rechecking it was found that an observation 8 was incorrect. Calculate the correct mean and standard deviation If it is replaced by 12.

asked Jul 2, 2014 by meena.p

1 answer

The mean and standard deviation of 20 observations are found to be 10 and 2 respectively. On rechecking it was found that an observation 8 was incorrect. Calculate the correct mean and standard deviation If wrong item is omitted.

asked Jul 2, 2014 by meena.p

1 answer

In what direction should a line be drawn through the point (1, 2) so that its point of intersection with the line x + y = 4 is at a distance $ \large\frac{\sqrt 6}{3}$ from the given point

asked Jul 1, 2014 by thanvigandhi_1

1 answer

The mean and standard deviation of six observations are $8$ and $4$ respectively. If each observation is multiplied by $3$, find the new mean and new standard deviation of the resulting observation.

asked Jul 1, 2014 by meena.p

1 answer

If the intercept of a line between the coordinate axes is divided by the point (–5 4) in the ratio 1 : 2, then find the equation of the line.

asked Jul 1, 2014 by thanvigandhi_1

1 answer

The sum and sum of squares corresponding to length x (in cm) and weight (y) in gm of 50 plant products are given below: $ \sum \limits _{i=1} ^{50} x_i=212, \qquad\sum \limits_{i=1}^{50}x_i^2 =902.8;\qquad \sum \limits _{i=1} ^{50} y_i=261, \qquad\sum \limits_{i=1}^{50}y_i^2 =1457.6$ Which is more varying , the length or weight?

asked Jul 1, 2014 by meena.p

1 answer

The following is the record of goals scored by team A in a football session. For Team B , mean number of goals scored per match was 2 with a standard deviation 1.25 goals. Find which team may be considered more consistent ?

asked Jul 1, 2014 by meena.p

1 answer

An analysis of monthly wages paid to workers in two firms A and B , belonging to the same industry, gives the following results. (i) Which firm A and B pays larger amount as monthly wages. (ii) which firm A or B shows greater variability in individual wages?

asked Jul 1, 2014 by meena.p

1 answer

A fair coin is tossed four times and a person win Rs.1 for each head and lose Rs.1.50 for each tail that turns up.From the sample space,calculate how many different amounts of money you can have after four tosses and the probability of having each of these amounts.

asked Jul 1, 2014 by sreemathi.v

1 answer

Find the equation of the lines which passes through the point (3, 4) and cuts off intercepts from the coordinate axes such that their sum is 14.

asked Jun 30, 2014 by thanvigandhi_1

1 answer

From the prices of shares A and Y below. Find out which is more stable in value.

asked Jun 30, 2014 by meena.p

1 answer

From the data given below state which group is more variable A or B?

asked Jun 30, 2014 by meena.p

1 answer

The diameters of circles(in mm) drawn in a design are given below . Calculate the std. deviation and mean diameter of the circles.

asked Jun 30, 2014 by meena.p

1 answer

Find mean and variance and standard deviation using short cut method.

asked Jun 30, 2014 by meena.p

1 answer

Which of the following can not be valid assignment of probabilities for outcomes of sample space $S=\{\omega 1,\omega 2,\omega 3,\omega 4,\omega 5,\omega 6,\omega 7\}$

asked Jun 30, 2014 by sreemathi.v

1 answer

Find mean and variance for the following frequency distribution :

asked Jun 27, 2014 by meena.p

1 answer

Find mean and variance for the following frequency distribution :

asked Jun 27, 2014 by meena.p

1 answer

An experiment consists of rolling a die and then tossing a coin once if the number on the die is even.If the number on the die is odd,the coin is tossed twice.Write the sample space for the experiment

asked Jun 26, 2014 by sreemathi.v

1 answer

Calculate the mean deviation about median for the age distribution of 100 persons given below.

asked Jun 26, 2014 by meena.p

1 answer

A coin is tossed .If the outcome is a head,a die is thrown.If the die shows up an even number,the die is thrown again.What is the sample space for the experiment.

asked Jun 26, 2014 by sreemathi.v

1 answer

Find the mean deviation about the median for the following data :

asked Jun 26, 2014 by meena.p

1 answer

If the coefficient of $x^7$ in the expansion of $(a^2x+b^{-1}x^{-1})^{11}$ is equal to the coefficient of $x^{-7}$ in $(ax-b^{-1}x^{-2})^{11}$ then $ab=$

asked Jun 25, 2014 by sreemathi.v

1 answer

If the middle term of $(\large\frac{1}{x}$$+x\sin x)^{10}$ is equal to $7\large\frac{7}{8}$ then value of $x$ is

asked Jun 25, 2014 by sreemathi.v

1 answer

Find the term independent of $x$ in the expansion of $(1+x+2x^3)(\large\frac{3}{2}$$x^2-\large\frac{1}{3x})^9$

asked Jun 24, 2014 by sreemathi.v

1 answer

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