# 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 Amazon.com

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?

https://brainmass.com/statistics/designing-studies/sample-vs-population-discrete-vs-continuous-interval-variables-341224

#### 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.

Population, sample, parameter, statistic, discrete variable and a continuous variable, independent and dependent variables, scale of measurement

1. A researcher is interested in the effects of humidity on the eating behavior rats. A group of 25 rats is housed in a controlled environment and the researcher measures the amount of food consumed by each rat with humidity set at 20% and again with the humidity set at 80%.

a. Identify the population

b. Identify the sample

2. Define the terms population, sample, parameter, and statistic. Explain the relationships among the terms

3. Statistical methods are classified into two major categories: descriptive and inferential. Describe the general purpose for the statistical methods in each category.

4. Define the concept of sampling error. Be sure that your definition includes the concepts of statistic and parameter.

16. Define and differentiate between a discrete variable and a continuous variable

17. A researcher studying the effects of environment on mood asks participation to sit alone in a waiting room for 15 minutes at the beginning of an experiment. Half of them are assigned to a room with dark blue walls, and the other half are assigned to a room with bright yellow walls. After 15 minutes in the waiting room, each participant is brought into the lab and given a mood-assessment questionnaire. The score on the mood questionnaire are then examined.

a. Identify the independent and dependent variables for this study

b. What scale of measurement is used for the independent variable?

18. For the following scores, find the value of each expression:

X= 5,2,1,4,

a. Sigma X , X=

b. Sigma X²

c. Sigma X)²

d. Sigma (X-1)

See attached file for full problem description.