Tag: variance and standard deviation

Questions Related to variance and standard deviation

Multiple choice range and mean deviation statistics and probability maths coefficient of variance variance and standard deviation

For a symmetrical distribution lower quartitl is 20 and upper quartile is 40.The value of 50th percentile is

  1. 20

  2. 40

  3. 30

  4. none of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

First quartile also called the lower quartile or the 25th percentile(splits off the lowest 25% of data from the highest 75%)
Second quartile also called the median or the 50th percentile (cuts data set in half)
Third quartile  also called the upper quartile or the 75th percentile (splits off the highest 25% of data from the lowest 75%)
Since its a symmetrical distribution therefore the median will be 30

Multiple choice range and mean deviation statistics and probability maths coefficient of variance variance and standard deviation

The formula for the coefficient of range is $\dfrac{\text{Range}}{a+b}$. Here, $a$ and $b$ denote:

  1. the mean and median of the data set

  2. the maximum and the minimum value of the data set

  3. the mean and mode value of the data set

  4. the minimum and mean value of the data set

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Range is the difference between the maximum value and the minimum value of the data set.


Let $a$ be the maximum value of the data set and
$b$ be the minimum value of the data set

Therefore, $range = a-b$

Coefficient of range is the relative measure of the dispersion.

It is given by $\text{coefficient of range}=\dfrac{a-b}{a+b}=\dfrac{range}{a+b}$

Multiple choice range and mean deviation statistics and probability maths coefficient of variance variance and standard deviation

The largest of $50$ measurements is $3.84$kg. If the range is $0.46$kg, find the smallest measurement.

  1. $3.38$kg.
  2. $2.38$kg.
  3. $6.38$kg.
  4. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$\Rightarrow$  Here, $L=3.84$ and $R=0.46$

$\Rightarrow$  $R=L-S$
  $0.46=3.84-S$
  $S=3.84-0.46$
$\therefore$  $S=3.38\,kg$
$\therefore$   Smallest measurement is $3.38\,kg$

Multiple choice range and mean deviation statistics and probability maths coefficient of variance variance and standard deviation

The mean deviation from the median is _________ that measured from any other value.

  1. equal to

  2. less than

  3. greater than

  4. None of these

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The value of the mean deviation is minimum if the deviations are taken from the median. So, it is less than that measured from any other value.

A series drawback of the mean deviation is that it cannot be used in statistical inference.

Multiple choice range and mean deviation statistics and probability maths coefficient of variance variance and standard deviation

The difference between the maximum and the minimum obervations in data is called the ____________.

  1. mean of the data

  2. range of the data

  3. mode of the data

  4. median of the data

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In arithmetic, the range of a set of data is the difference between the largest and smallest values.

So, difference between minimum and maximum values is called range.