Question 1 :
The mean salary paid per week to $1000$ employees of an establishment was found to be Rs. $900$. Later on, it was discovered that the salaries of two employees were wrongly recorded as Rs. $750$ and Rs. $365$ instead of Rs. $570$ and Rs. $635$. Find the corrected mean salary.

Question 3 :
If mean of given data is 12 then value of p is <br><table class="wysiwyg-table"><tbody><tr><td>x</td><td>4</td><td>8</td><td>p</td><td>16</td><td>20</td></tr><tr><td>f</td><td>5</td><td>3</td><td>12</td><td>5</td><td>4</td></tr></tbody></table>

Question 4 :
The mean of 20 items of a data is 5 and if each item is multiplied by 3 then the mean will be

Question 5 :
<table class="wysiwyg-table"><tbody><tr><td>x</td><td>10</td><td>15</td><td>20</td><td>25</td><td>35</td></tr><tr><td>f</td><td>6</td><td>p</td><td>26</td><td>10</td><td>8</td></tr></tbody></table>If means of the above is 21 then values of p is

Question 6 :
<table class="table table-bordered"><tbody><tr><td> Students</td><td> 2</td><td> 10</td><td> 15</td><td> 20</td><td> 25</td></tr><tr><td> Marks</td><td> 100</td><td> 90</td><td> 75</td><td> 80</td><td> 85</td></tr></tbody></table>Find the mean for the following data using direct method.

Question 7 :
<table class="table table-bordered"><tbody><tr><td> Number of employees</td><td>2 </td><td> 5</td><td> 6</td><td> 7</td><td> 8</td></tr><tr><td> Daily wedges</td><td> 500</td><td> 750</td><td>200 </td><td> 400</td><td> 600</td></tr></tbody></table>Estimate the mean of the following data using direct method.

Question 8 :
If the mean of following frequency. distribution. is $2.6$, then the<span> value of $f$ is<br/></span><table class="wysiwyg-table"><tbody><tr><td>$x_i$</td><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td></tr><tr><td>$f_i$</td><td>5</td><td>4</td><td>f</td><td>2</td><td>3</td></tr></tbody></table>

Question 10 :
The mean of the squares of the first n natural numbers is

Question 11 :
Frequency distribution of distance travelled in kms. per liter of petrol by different mopeds is given below.<br/><table class="wysiwyg-table"><tbody><tr><td>Distance travelled (in km/lit)</td><td>62 - 65</td><td>65 - 68</td><td>68 - 71</td><td>71 - 74</td><td>74 - 77</td><td>77 - 80</td><td>80 - 83</td></tr><tr><td>No.of mopeds</td><td>5</td><td>8</td><td>12</td><td>28</td><td>35</td><td>10</td><td>2</td></tr></tbody></table>Find mean distance travelled per liter of petrol by a moped.

Question 12 :
<table class="table table-bordered"><tbody><tr><td> x</td><td> 6</td><td> 8</td><td> 10</td><td> 12</td><td> 14</td></tr><tr><td> f</td><td> 9</td><td> 7</td><td> 15</td><td>13 </td><td> 6</td></tr></tbody></table>Find the arithmetic mean of the following data

Question 13 :
<span>The value of houses in a particular area are shown in the table.<br/></span><table class="wysiwyg-table"><tbody><tr><td>Value per house (in lakhs)</td><td>$10-20$</td><td>$20-30$</td><td>$30-40$</td><td>$40-50$</td><td>$50-60$</td></tr><tr><td>Number of houses</td><td>$12$</td><td>Y</td><td>$5$</td><td>$8$</td><td>$3$</td></tr></tbody></table><p>Given the mean value of the houses is $30.14$lakhs. and assumed mean is $35$</p>

Question 16 :
<span>You grew sixty plants using special soil. You measure their lengths and the values are tabulated below.<br/></span><table class="wysiwyg-table"><tbody><tr><td>Length(cm)</td><td>$120-125$</td><td>$125-130$</td><td>$130-135$</td><td>$135-140$</td><td>$140-145$</td><td>$145-150$</td></tr><tr><td>Number of plants</td><td>$8$</td><td>$10$</td><td>Y</td><td>$16$</td><td>$8$</td><td>$12$</td></tr></tbody></table><p><span>The mean length of the plants is $136$cm. Find y in the table.</span></p>

Question 17 :
The mean marks scored by $40$ students were found to be $60$. Later it was observed that a score of $48$ was misread as $84$. Then the correct mean is __________.

Question 18 :
Consider the table given below<br><table class="wysiwyg-table"><tbody><tr><td>Marks</td><td>0-10</td><td>10-20</td><td>20-30</td><td>30-40</td><td>40-50</td><td>50-60</td></tr><tr><td>Number of Students</td><td>12</td><td>18</td><td>27</td><td>20</td><td>17</td><td>6</td></tr></tbody></table>The arithmetic mean of the marks given above is

Question 20 :
If the number of observations in the data is more and/or figures are large, we use _____ for calculating mean.