# Web Activities

Click on the following links. Please note these will open in a new window.

#### Converting different raw scores into z-scores to examine area-under the curve

Go to this following website: http://onlinestatbook.com/2/calculators/normal_dist.html

The following website has a z-distribution that allows you to see the area under the curve as you change different parameters. We know that the distribution of typical IQ scores (m = 100; s = 15). Now, use the buttons below to examine the shaded area and the exact probability that the IQ score of one person, randomly selected from the population, will be: (1) Above 115, (2) Below 90, (3) between 90 and 120, and (4) outside of 70 and 130. Report the answer for each value. Now, change each of the values above and see how it changes the area-under-the-curve.

#### Examining area-under-the-curve for different z-scores

Go to the following website: http://davidmlane.com/hyperstat/z_table.html

The following website has a z-distribution that allows you to see the raw scores as you change different parameters. Let’s take a look at the distribution of typical IQ scores (m = 100; s = 15). First, click on “Values from an Area (Use to compute Z for confidence intervals)” button. First, specify the parameters to have a Mean of 100 and a Standard Deviation of 15. Now, use the buttons below to examine the shaded area and the raw scores for each of the areas p = .05 (above and below). Next, use the buttons below to examine the shaded area and the raw scores for each of the areas p = .95 (between and outside). Report the answer for each value. Now, change each of the values above and see how it changes the raw scores.

#### How much will you need to spend to buy a new car?

Go to your favorite search engine and search for the average car prices for last year (you will need to also find the standard deviation). Car segments vary quite a bit in average price (e.g., compact car, luxury car, sports car, van, etc.). Find the average price for a few specific segments of cars. With this information, determine your own the z-score for different car segments. Report the answer to the following questions: What is the approximate proportion of the population below this segment? What is the approximate population above this segment?