Standard Deviation of Grouped Data by Mean Method

Q. 48 students were asked to write the total number of hours per week they spent on watching television. With this information find the standard deviation of hours spent on watching television.

$\begin{array}{cccccccc}x& 6& 7& 8& 9& 10& 11& 12\\ f& 3& 6& 9& 13& 8& 5& 4\end{array}$

1. 1.6
2. 2.6
3. 3.2
4. 3.8

Q. The marks scored by the students in a test are given below.
$\begin{array}{cccccc}x& 4& 6& 8& 10& 12\\ f& 7& 3& 5& 9& 5\end{array}$
Find the standard deviation of their marks by assumed mean method.

1. 5.22
2. 3.91
3. 2.87
4. 4.48

Q.

The following is the record of goals scored by team A in a football session:

$\begin{array}{cccccc}No.ofgoalsscored& 0& 1& 2& 3& 4\\ No.ofmatches& 1& 9& 7& 5& 3\end{array}$

For the team B, mean number of goals scored per match was 2 with standard deviation 1.25 goals. Find which team may be considered more consistent?

Q. 20 students were asked to write the number of hours they spent per week on studies. With the given information find the standard deviation of the number of hours spent using Mean method.

$\begin{array}{ccccc}{x}_i& 2& 4& 5& 10\\ f_i& 5& 10& 4& 1\end{array}$

1. 1.73
2. 2.24
3. 3.75
4. 4.29

Q. 20 students were asked to write the number of hours they spent per week on studies. With the given information find the standard deviation of the number of hours spent using Mean method.

$\begin{array}{ccccc}{x}_i& 2& 4& 5& 10\\ f_i& 5& 10& 4& 1\end{array}$

1. 1.73
2. 2.24
3. 3.75
4. 4.29

Q. The Goals scored by players in a game are given below.
$\begin{array}{ccccc}x& 3& 4& 5& 6\\ f& 2& 3& 4& 5\end{array}$
Find the standard deviation of their goals scored by assumed mean method.

1. 1.059
2. 2.212
3. 2.314
4. 4.215

Q. The Goals scored by players in a game are given below.
$\begin{array}{ccccc}x& 3& 4& 5& 6\\ f& 2& 3& 4& 5\end{array}$
Find the standard deviation of their goals scored by assumed mean method.

1. 2.212
2. 2.314
3. 1.059
4. 4.215

Q. Draw the graph of straight line $y=-2x+3.$ Use your graph to find the area between the line and co-ordinate axes.

1. $4.66$ sq.units
2. $3.25$ sq.units
3. $2.25$ sq.units
4. $5.66$ sq.units