# Parameter and Statistic Measurements

1.What is a parameter?

What is a statistic?

What are statistics used for?

2. Give an example of each of these levels of measurement: Nominal, Ordinal, Ratio

3. What, in your opinion, is the most important step in a research design? Explain why and give at least two reasons. (Should be able to do this in about 50 words or so. Don't go overboard!)

4. If we have a normal distribution that has a mean of 200 and a standard deviation of 15, find the proportion of the curve that:

Falls between 170 and 230

Falls above 245

5.

For a normal curve with a mean of 100 and standard deviation of 8, find the two points that are equidistant from the mean, X1 to the left and X2 to the right, that include 95% of the population.

6.

IQ's have a mean of 100 and a standard deviation of 15. Find the IQ score that defines the top 2.5% of all IQ scores.

#### Solution Preview

1.What is a parameter?

A parameter is a quantity that defines certain characteristics of system or functions.

What is a statistic?

A statistic (singular) is the result of applying a function (statistical algorithm) to a set of data.

What are statistics used for?

To calculate

1 Sample mean and sample median

2. Sample variance and sample standard deviation

3. Sample quantities besides the median e.g. quartiles and percentiles

4. t statistics, chi-square statistics, f statistics

5. Order statistics, including sample maximum and minimum

6. Sample moments and function therefore, ...

#### Solution Summary

The parameter and statistic measurements for a normal distribution is analyzed. The proportion of a curve is discovered.