The mean of the following frequency distribut | vedclass

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(C) To find the mean,we first calculate the class mark $(x_i)$ for each interval:$10-20: x_1 = 15$$20-30: x_2 = 25$$30-40: x_3 = 35$$40-50: x_4 = 45$$

Vedclass · Accepted Answer

$7$

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(C) To find the mean,we first calculate the class mark $(x_i)$ for each interval:$10-20: x_1 = 15$$20-30: x_2 = 25$$30-40: x_3 = 35$$40-50: x_4 = 45$$50-60: x_5 = 55$$60-70: x_6 = 65$$70-80: x_7 = 75$The sum of frequencies $\sum f_i = 5 + 3 + 4 + f + 2 + 6 + 13 = 33 + f$.The sum of products $\sum f_i x_i = (5 	imes 15) + (3 	imes 25) + (4 	imes 35) + (f 	imes 45) + (2 	imes 55) + (6 	imes 65) + (13 	imes 75)$$= 75 + 75 + 140 + 45f + 110 + 390 + 975 = 1765 + 45f$.Given mean $\bar{x} = 52$,we use the formula $\bar{x} = \frac{\sum f_i x_i}{\sum f_i}$:$52 = \frac{1765 + 45f}{33 + f}$$52(33 + f) = 1765 + 45f$$1716 + 52f = 1765 + 45f$$52f - 45f = 1765 - 1716$$7f = 49$$f = 7$.

Class	$10-20$	$20-30$	$30-40$	$40-50$	$50-60$	$60-70$	$70-80$
Frequency	$5$	$3$	$4$	$f$	$2$	$6$	$13$

Class	$0-10$	$10-20$	$20-30$	$30-40$	$40-50$	$50-60$	$60-70$
Frequency	$5$	$12$	$18$	$40$	$15$	$7$	$3$

Height (in $cm$)	Frequency	Cumulative frequency
$150-155$	$12$	$a$
$155-160$	$b$	$25$
$160-165$	$10$	$c$
$165-170$	$d$	$43$
$170-175$	$e$	$48$
$175-180$	$2$	$f$
Total	$50$	-

The mean of the following frequency distribution is $52$. Find the missing frequency $f$.

Class $10-20$ $20-30$ $30-40$ $40-50$ $50-60$ $60-70$ $70-80$

Frequency $5$ $3$ $4$ $f$ $2$ $6$ $13$

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Rachana had an average score of $45$ from $6$ tests. Her teacher dropped her lowest score,which is $30$,and calculated the average of the remaining scores to decide her grade. Which of the following gives her new average score?

.......... is not a measure of central tendency.

Find the mean,median and mode of the following frequency distribution:

Class $0-10$ $10-20$ $20-30$ $30-40$ $40-50$ $50-60$ $60-70$

Frequency $5$ $12$ $18$ $40$ $15$ $7$ $3$

If $3 \bar{x} = 2 M = 60,$ then $Z = \dots$

Find the unknown entries $a, b, c, d, e, f$ in the following distribution of heights of students in a class:

Height (in $cm$) Frequency Cumulative frequency

$150-155$ $12$ $a$

$155-160$ $b$ $25$

$160-165$ $10$ $c$

$165-170$ $d$ $43$

$170-175$ $e$ $48$

$175-180$ $2$ $f$

Total $50$ -

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The mean of the following frequency distribution is $52$. Find the missing frequency $f$. Class $10-20$ $20-30$ $30-40$ $40-50$ $50-60$ $60-70$ $70-80$ Frequency $5$ $3$ $4$ $f$ $2$ $6$ $13$