Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; plgContentJComments has a deprecated constructor in /var/www/astarmathsandphysics/plugins/content/jcomments/jcomments.php on line 25 Call Stack: 0.0002 360424 1. {main}() /var/www/astarmathsandphysics/index.php:0 0.0551 1209024 2. Joomla\CMS\Application\SiteApplication->execute() /var/www/astarmathsandphysics/index.php:49 0.0551 1209024 3. Joomla\CMS\Application\SiteApplication->doExecute() /var/www/astarmathsandphysics/libraries/src/Application/CMSApplication.php:267 0.2181 4123928 4. Joomla\CMS\Application\SiteApplication->dispatch() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:233 0.2195 4151272 5. Joomla\CMS\Component\ComponentHelper::renderComponent() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:194 0.2203 4168984 6. Joomla\CMS\Component\ComponentHelper::executeComponent() /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:356 0.2205 4199504 7. require_once('/var/www/astarmathsandphysics/components/com_content/content.php') /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:381 0.2216 4222224 8. ContentController->execute() /var/www/astarmathsandphysics/components/com_content/content.php:42 0.2216 4222224 9. ContentController->display() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:710 0.2719 4899904 10. ContentController->display() /var/www/astarmathsandphysics/components/com_content/controller.php:113 0.2756 5092056 11. Joomla\CMS\Cache\Controller\ViewController->get() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:663 0.2762 5112984 12. ContentViewArticle->display() /var/www/astarmathsandphysics/libraries/src/Cache/Controller/ViewController.php:102 0.2878 5304344 13. Joomla\CMS\Plugin\PluginHelper::importPlugin() /var/www/astarmathsandphysics/components/com_content/views/article/view.html.php:189 0.2878 5304600 14. Joomla\CMS\Plugin\PluginHelper::import() /var/www/astarmathsandphysics/libraries/src/Plugin/PluginHelper.php:182 Deprecated: Methods with the same name as their class will not be constructors in a future version of PHP; JCommentsACL has a deprecated constructor in /var/www/astarmathsandphysics/components/com_jcomments/classes/acl.php on line 17 Call Stack: 0.0002 360424 1. {main}() /var/www/astarmathsandphysics/index.php:0 0.0551 1209024 2. Joomla\CMS\Application\SiteApplication->execute() /var/www/astarmathsandphysics/index.php:49 0.0551 1209024 3. Joomla\CMS\Application\SiteApplication->doExecute() /var/www/astarmathsandphysics/libraries/src/Application/CMSApplication.php:267 0.2181 4123928 4. Joomla\CMS\Application\SiteApplication->dispatch() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:233 0.2195 4151272 5. Joomla\CMS\Component\ComponentHelper::renderComponent() /var/www/astarmathsandphysics/libraries/src/Application/SiteApplication.php:194 0.2203 4168984 6. Joomla\CMS\Component\ComponentHelper::executeComponent() /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:356 0.2205 4199504 7. require_once('/var/www/astarmathsandphysics/components/com_content/content.php') /var/www/astarmathsandphysics/libraries/src/Component/ComponentHelper.php:381 0.2216 4222224 8. ContentController->execute() /var/www/astarmathsandphysics/components/com_content/content.php:42 0.2216 4222224 9. ContentController->display() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:710 0.2719 4899904 10. ContentController->display() /var/www/astarmathsandphysics/components/com_content/controller.php:113 0.2756 5092056 11. Joomla\CMS\Cache\Controller\ViewController->get() /var/www/astarmathsandphysics/libraries/src/MVC/Controller/BaseController.php:663 0.2762 5112984 12. ContentViewArticle->display() /var/www/astarmathsandphysics/libraries/src/Cache/Controller/ViewController.php:102 0.9148 13722504 13. JEventDispatcher->trigger() /var/www/astarmathsandphysics/components/com_content/views/article/view.html.php:199 0.9151 13722904 14. plgContentJComments->update() /var/www/astarmathsandphysics/libraries/joomla/event/dispatcher.php:160 0.9151 13722904 15. plgContentJComments->onContentAfterDisplay() /var/www/astarmathsandphysics/libraries/joomla/event/event.php:70 0.9153 13731152 16. plgContentJComments->onAfterDisplayContent() /var/www/astarmathsandphysics/plugins/content/jcomments/jcomments.php:339 0.9156 13732888 17. JComments::show() /var/www/astarmathsandphysics/plugins/content/jcomments/jcomments.php:282 0.9162 13765936 18. JCommentsFactory::getACL() /var/www/astarmathsandphysics/components/com_jcomments/jcomments.php:188 0.9162 13766336 19. spl_autoload_call() /var/www/astarmathsandphysics/components/com_jcomments/classes/factory.php:274 0.9163 13766416 20. JLoader::load() /var/www/astarmathsandphysics/components/com_jcomments/classes/factory.php:274

Sampling Methods

Gathering statistics involves time and effort. It is a necessary procedure – governments need to know how many schools to build, or policemen to employ, and companies need to know which products people will buy. They could go out and ask everyone, but this would mean a lot of time and effort needed to be spent, much of it unnecessary.

Instead of asking everyone, we could carry out a survey. This involves selecting a number of individuals that are representative of the population. The process of picking which individuals to sample is called 'sampling'. There are four different types of sampling.

  1. Random – individuals are selected at random. In practice it can be difficult to find a random sample. If you randomly ask people shopping for example, you will probably be asking mostly women, because MEN HATE SHOPPING!

  2. Systematic – Gather a random selection then select every 10th or 20th individual from that selection to sample. Obviously this is not a truly random sample. The selection will have to be ordered in some way. If they are ordered with respect to height for example, with 99 people, then the last, tallest person will have no chance of being selected.

  3. Stratified – If the population falls into several different groups, choose some of the groups to sample from, then pick a random selection from those groups. This will mean that some groups are not represented in the sample.

  4. Quota – If the population to be sampled consists of distinct groups, then individuals are picked from each group to reflect the proportion they have in the population. In practice it may be difficult to fill each quota. If you are seeking to asking men and women which holiday they would prefer according to the proportion they represent in the population, it will probably be hard to obtain enough answers from men because they tend to be busier, and they may not care at all where they go on holiday (beer tastes the same everywhere).

    Quota sampling is probably the most used method. Suppose a sample of 50 is to be taken from a population consisting of the following groups and numbers.

    Group

    Frequency

    Men

    25

    Women

    54

    Boys

    76

    Girls

    69

There are 25+54+76+69=224 individuals.

The number of men to be sampled is

The number of women to be sampled is

The number of boys to be sampled is

The number of girls to be sampled is

Check 6+12+17+50=50.

Add comment

Security code
Refresh