Week # 5

StudentoftheYear

University of Phoenix

QRB501: Quantitative Reasoning for Business

Robert Batiste

May 4, 2009

Sevilla & Somers Text

Activity 17.1(1 only)

In the first part of this activity, you will generate some data that should have an approximately normal (or bell-shaped) distribution. In the second part, you will use the definition of standard deviation and compare the standard deviations for two different data sets.

1. Work with a partner to generate the following data.

a. Toss 10 coins and record the number of heads you obtained.

5

b. Repeat this 24 more times until you have a list of 25 numbers, each of them between 0 and 10. [pic]

c. Retrieve the file “EA17.1 Coins and Presidents.xls” from the CD or website, and you will find the results of 35 tosses of 10 coins that someone else carried out. When you first retrieve the file, column B contains the number of times 0 heads was obtained in the 35 tosses of 10 coins, the number of times 1 head was obtained in the 35 tosses, and so on, up to the number of times 10 heads was obtained. Add your results to the list so you have a total of 60 in column B. [pic]

d. Create a scatterplot of these data, using one of the versions of the scatterplot with the dots connected. Describe what your curve looks like, including where it is “centered” and what its “spread” is. [pic]

The scatter plot has a mountain look. The apex is at 5 and its spread expands from 0 to 10. The frequency of heads fell between 3-5.

e. Change your graph to a bar graph (instructions follow). [pic]

f. Print your bar graph, with appropriate titles on the axes, and by hand draw in a bell-shaped curve that “fits” this data. How does your hand drawn curve compare with the curve you described in part d of this question? [pic]

When the bell shaped curved is compared to the scatter plot graph, the bell shaped curve demonstrates a...

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