### Grouping data - class-X

Tally marks are used find

Satish got the following marks in his weekly class tests out of $50$:

$48$, $32$, $36$, $42$, $38$, $35$, $39$, $49$, $34$, $14$, $32$, $37$, $31$ What should he expect in the next weekly test out of the following?

(i) between $40 - 50$

(ii) between $30 - 40$

12 | 24 | 36 | 48 | 60 | 72 |
---|---|---|---|---|---|

24 | 48 | 60 | 72 | 50 | 30 |

50 | 45 | 50 | 75 | 50 | 34 |

The number of students in a quiz competition scores are in the table. How many students scored $50$ marks?

Consider the following frequency distribution:

Class | $0-10$ | $0-20$ | $0-30$ | $0-40$ | $0-50$ |
---|---|---|---|---|---|

Frequency | $3$ | $8$ | $14$ | $20$ | $25$ |

What is the above frequency distribution known as?

Consider the following statements :

1. A continuous random variable can take all values in an interval.

2. A random variable which takes a finite number of values is necessarily discrete.

3. Construction of a frequency distribution is based on data which are discrete.

Which of the above statements are correct ?

The marks (out of 10) obtained by 28 students in a Mathematics test are listed as below :

8, 1, 2, 6, 5, 5, 5, 0, 1, 9, 7, 8, 0, 5, 8, 3, 0, 8, 10, 10, 3, 4, 8, 7, 8, 9, 2, 0

The number of students who obtained marks more than or equal to 5 is

The frequency distribution of marks obtained by $60$ students of a class is given.

X | $30-34$ | $40-44$ | $45-49$ | $50-54$ | $55-59$ | $60-64$ |
---|---|---|---|---|---|---|

f | $3$ | $5$ | $12$ | $18$ | $14$ | $62$ |

Find mode of the distribution.

The median and mode of frequency distribution are 525 and 500, then mean of same frequency distribution is -

Mode of distribution

$Marks\begin{bmatrix} 4 & 5 & 6 & 7 & 8 \end{bmatrix}\ No\quad of\quad students\quad \begin{bmatrix} 3 & 5 & 10 & 6 & 1 \end{bmatrix}$

The cumulative frequency distribution corresponding to 20 percentile is ______.

Find a 9596 confidence interval for the population mean from the following data:

Sample size n = 65, Mean = 6300, Standard deviation = 9.5, N=1000.

What are the shortcomings of frequency distribution?

If $y \, = \, x^3 \, + \, 40$, find $\displaystyle \frac{d^2y}{dx^2} =$____.

A tabular summary of a set of data showing classes of the data and the fraction of the items belonging to each class is called ______________.

In a truly normal frequency distribution _________.