# Recent questions tagged statistics 0 votes
1 answer
1
Following marks are obtained by the students in a test: $81,72,90,90,86,85,92,70,71,83,89,95,85,79,62$. Range of the marks is $9$ $17$ $27$ $33$
3 votes
2 answers
2
For two data sets, each of size $5$, the variances are given to be $4$ and $5$ and the corresponding means are given to be $2$ and $4$ respectively. The variance of the combined data is? $11/2$ $6$ $13/2$ $5/2$
2 votes
1 answer
3
A class of first year B.tech students is composed of four batches A, B, C and D, each consisting of $30$ students. It is found that the sessional marks of students in Engineering Drawing in batch C have a mean of $6.6$ and standard deviation of $2.3$. The mean and the standard deviation of ... class. Due to this, the marks of a student in batch C are changed from $8.5$ to $6.0$ $7.0$ $8.0$ $9.0$
1 vote
1 answer
4
The following sequence of numbers is arranged in increasing order: $1,x,x,x,y,y,9,16,18$. Given that the mean and median are equal, and are also equal to twice the mode, the value of $y$ is $5$ $6$ $7$ $8$
1 vote
1 answer
5
The second moment of a Poisson-distributed random variable is 2. The mean of the variable is .... My question on solving we get 2 values of lamda(ie mean) .One is -2 and the other is 1 .So which one to choose?
1 vote
0 answers
6
For what value of 'k' (in terms of $X_{i}$'s) following functions will attain their minimum value $\rightarrow$ $F_{1}(k)$ = $\sum_{i=0}^{n} \left | X_{i} - k \right |$ $F_{2}(k)$ = $\sum_{i=0}^{n}\left ( X_{i} - k \right )^{2}$ If possible, please provide some valid proof for supporting your answer ?
0 votes
1 answer
7
the harmonic mean of two positive integers p and q is 3, given that [ (6p+1)/(7q-4) ] <(p/q), what could be the value of q? a)q<=4 b)q>9 c)q<8 d)q>=13
1 vote
1 answer
8
In a company with $100$ employees, $45$ earn $Rs. 20,000$ per month, $25$ earn $Rs. 30000$, $20$ earn $Rs. 40000$, $8$ earn $Rs. 60000$, and $2$ earn $Rs. 150,000$. The median of the salaries is $Rs. 20,000$ $Rs. 30,000$ $Rs. 32,300$ $Rs. 40,000$
5 votes
2 answers
9
Students taking an exam are divided into two groups, P and Q such that each group has the same number of students. The performance of each of the students in a test was evaluated out of $200$ marks. It was observed that the mean of group P was $105$, while that of ... Most students of group Q scored marks in a narrower range than students in group P. The median of the marks of group P is $100$.
2 votes
1 answer
10
3 votes
3 answers
11
What is the median of data if its mode is 15 and the mean is 30? 30 25 22.5 27.5
4 votes
3 answers
12
The arithmetic mean of attendance of 49 students of class A is 40% and that of 53 students of class B is 35%. Then the percentage of arithmetic mean of attendance of class A and B is 27.2% 50.25% 51.13% 37.4%
3 votes
2 answers
13
If the mean of a normal frequency distribution of 1000 items is 25 and its standard deviation is 2.5, then its maximum ordinate is $\frac{1000}{\sqrt{2 \pi} } e^{-25}$ $\frac{1000}{\sqrt{2 \pi} }$ $\frac{1000}{\sqrt{2 \pi} } e^{-2.5}$ $\frac{400}{\sqrt{2 \pi} }$
9 votes
6 answers
14
The statistics of runs scored in a series by four batsmen are provided in the following table. Who is the most consistent batsman of these four? ... $K$ $L$ $M$ $N$
2 votes
2 answers
15
The arithmetic mean of five different natural numbers is $12$. The largest possible value among the numbers is $12$ $40$ $50$ $60$
1 vote
1 answer
16
what is positively skewed ,symmetric and negatively skewed distribution?
5 votes
2 answers
17
Let $A$ and $B$ be non-empty disjoint sets of real numbers. Suppose that the average of the numbers in the first set is $\mu_{A}$ and the average of the numbers in the second set is $\mu_{B}$; let the corresponding variances be $v_{A}$ and $v_{B}$ respectively. If the average of the elements in $A \cup B$ ... $p.v_{A}+ (1 - p). v_{B} + (\mu_{A}- \mu_{B})^{2}$
3 votes
2 answers
18
Q) Let $x$ be normal variable with mean $8$ and standard deviation $4$ then $p(X\leq5)$ is A). Greater than zero but less than $0.5$ B). Greater than $0.75$ C). Greater than $0.5$ but less than $1$ D). Equal to $0.5$
13 votes
2 answers
19
Which of the following assertions are CORRECT? P: Adding $7$ to each entry in a list adds $7$ to the mean of the list Q: Adding $7$ to each entry in a list adds $7$ to the standard deviation of the list R: Doubling each entry in a list doubles the mean of the list S: Doubling each entry in a list leaves the standard deviation of the list unchanged $P$, $Q$ $Q$, $R$ $P$, $R$ $R$, $S$
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