Your School's Whatsapp Group - Join Us now
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

The mean of the numbers 3, 6, 4, x, and 7 is 5. Find the...

Mathematics
JAMB 2003

The mean of the numbers 3, 6, 4, x, and 7 is 5. Find the standard deviation.

  • A. \(\sqrt{2}\)
  • B. \(\sqrt{3}\)
  • C. 2
  • D. 3
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Your School's Whatsapp Group - Join Us now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Correct Answer: Option A
Explanation

Standard deviation = \(\frac{\sum(x - \overline{x})^2}{\text{n}}\)

\(\overline{x}\) = \(\frac{ 3 + 6 + 4 + x + 7}{5}\) = 5

= 20 + x = 25

x = 25 - 20 = 5.

x

x - \(\overline{x}\)

(x - \(\overline{x}\))\(^2\)

3

3 - 5

-2 = 4

4

4 - 5

-1 = 1

5

5 - 5

0 = 0

6

6 - 5

1 = 1

7

7 - 5

2 = 4

 

 

\(\sum\) (x - \(\overline{x}\))\(^2\) = 10

 

Standard deviation = \(\frac{\sum(x - \overline{x})^2}{\text{n}}\) = \(\frac{\sqrt{10}}{5}\) = \(\sqrt{2}\)

There is an explanation video available below.


Report an Error Ask A Question Download App
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Your School's Whatsapp Group - Join Us now
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now

Explanation Video

WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Your School's Whatsapp Group - Join Us now

Contributions ({{ comment_count }})

Please wait...

{{ settings.no_comment_msg ? settings.no_comment_msg : 'There are no comments' }}

Quick Questions

Post your Contribution

Please don't post or ask to join a "Group" or "Whatsapp Group" as a comment. It will be deleted. To join or start a group, please click here

{{ quote.posted_by.display_name }}
{{ settings.form_textarea_description }}
 
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Post UTME Past Questions Agent
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
Your School's Whatsapp Group - Join Us now
Post-UTME Past Questions - Original materials are available here - Download PDF for your school of choice + 1 year SMS alerts
Post UTME Past Questions Agent
WAEC and NECO CBT Software for Computers and Laptops - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now
WAEC and NECO CBT App for Mobile Devices - Candidates, Schools, Centres, Resellers - 100% Offline -Download Now