By ‘sample’ they mean the individuals that were chosen to take part in the experiment. You cannot perform the experiment on the entire population, so you try to make sure that your sample is ‘representative of’ (ie actually reflects) the population as a whole.

The hypothesis is the thing that the experiment is trying to demonstrate. Without this, it is hard to design a good experiment (people often seem to forget it, however).

For example, in an experiment regarding plant fertilizers, the dependent variable is the thing that you are measuring (ie growth) and the independent variable is the thing that you vary (ie the type of fertilizer). The hypothesis might be that ‘fertilizers rich in phosphate are best at promoting leaf growth’.

The sample is population it is asking to answer the questions. So if you were giving a survey to teens 16-19 the sample would be however many teens male and female from ages 16-19. The sample is not representative if it cannot be generalized to the broader population. For example if you were doing a survey on how many people had health insurance and you found 80% but you only asked rich people your sample is not representative. The hypothesis is what the study is trying to figure out. Most of the time it’s a correlation like poor diets lead to obesity. The independent variable is what the experimenter can change for example if you wanted to see if eating healthy had an effect on mood, the independent variable would be eating healthy because you can have one group eat healthy and one not and then the dependent variable would be mood.

“What sample did it use” is just a fancy way of saying, “Who did they ask?”

For instance, in the “sex surveys” you might find in Redbook or Cosmo, it might say something like:

“71% of women said they like being kissed on the lips”

“29% of women said they like being kissed on the cheeks”

Sometimes in small print it will say “Survey of 150 women on the telephone” or perhaps the title will say, “We asked 1000 women between the ages of 18-34 about sex…”

Just look at your article and see what the sample is. Then, when you have to “comment on the representativeness” just ask yourself “does that group make sense?”

For instance if the survey was about airports, but the survey was taken at a train station, the sample doesn’t “represent” the an appropriate group for that study.

I hope that helps!

Regards,

Mysstere

DIY