10. Five mark exercise problems - I

1. A teacher asked the students to complete \(60\) pages of a record note book. Eight students have completed only \(32\), \(35\), \(37\), \(30\), \(33\), \(36\), \(35\) and \(37\) pages. Find the standard deviation of the pages yet to be completed by them.

 

Answer:

 

The standard deviation \(=\)

 

2. Find the variance and standard deviation of the wages of \(9\) workers given below: \(₹ 310\), \(₹ 290\), \(₹ 320\), \(₹ 280\), \(₹ 300\), \(₹ 290\), \(₹ 320\), \(₹ 310\), \(₹ 280\).

 

Answer:

 

Variance \(=\)

 

Standard deviation \(=\)

 

3. A wall clock strikes the bell once at \(1\) o' clock, \(2\) times at \(2\) o' clock, \(3\) times at \(3\) o' clock and so on. How many times will it strike in a particular day. Find the standard deviation of the number of strikes the bell make a day.

 

Answer:

 

Standard deviation \(=\)