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Sample vs population; discrete vs continuous interval variables

Just a small explanation needed for each.

1 Sample vs. Population: The health study of North Trondelang County of Norway (HUNT) surveyed more than 60,000 people in a Norwegian county and reported that 'people who have gastrointestinal symptoms, such as nauseas, are more likely to have anxiety disorders or depression than people who do not have such symptoms.'

a) What is the sample used by these researchers?
b) What is the population to which the researchers would like to extend their findings?

2- Discrete vs. continuous interval variables: For each of the following examples, state whether the interval is discrete or continuous.

a) The capacity, in terms of songs, of an iPod
b) The playing time of an individual song
c) The cost in cent to download a song legally
d) The number of posted reviews that CD has on
e) The weight of an MP3 player

3- Identifying independent variables: For each of the hypotheses listed in Exercise 1.9, identify the independent variable and the most likely levels of that independent variable

a) Teenagers are better at video games than are adults in their 30's
b) Spanking children leads them to be more violent
c) Weights Watchers leads to more weight loss if you go to meetings than if you participate online
d) Students do better in statistics if they study with other people than if they study alone
e) Drinking caffeinated beverages with dinner makes it harder to get to sleep at night

4 Within - groups vs. between groups: Noting the market increases in weight across the population, many researchers, nutrionists, and physicians have struggled to find ways to stem the tide of obesity in many Western countries. A number of exercises programs have been advocated by these clinicians and researchers, and there has been a flurry of research to determine their effectiveness. Pretend that you are in charge of a research program to examine the effects of an exercise program on weight loss in comparison with a non-exercise program.

a) Describe how you could study this exercise program using a between groups research design
b) Describe how you would study this exercise program using a within groups design
c) What is a potential confound of a within groups design?

Solution Preview

1) What is the sample? In this case, it would be the 60,000 people in the Norwegian country that was sampled by HUNT.
What is the population? It would be the entire country of Norway. You might even be able to extend it beyond Norway, and state that it could be generalized to similar people such as in the rest of Scandinavia.

2) - A type of data is discrete if there are only a finite number of possible values or if there is a space on the number line between each 2 possible values.
Continuous variable are measured on a scale that can be divided.
Continuous data makes up the rest of numerical data. This is a type of data that is usually associated with some sort of physical measurement.

HINT: One general way to tell if data is continuous is to ask yourself if it is possible for the data to take on values that are fractions or decimals. If your answer is yes, this is usually continuous data.

a) The capacity, in terms of songs, of an iPod - Since there is only a finite number of songs that you put on your iPod then, DISCRETE

b) The playing time of an individual song - since a song can be 3 min and 25.4 seconds (a fraction of a minute), then it is CONTINUOUS.

c) The cost in cent to download a song legally - Since the unit of measurement of CENT (not dollars), and you ...

Solution Summary

Sample versus population and discrete versus continuous interval variables are examined.