# Math 221 Random Sampling

Topics: Median, Standard deviation, Quartile Pages: 3 (602 words) Published: February 9, 2011
Math 221
Week 2 Lab

Part 1. Random Sampling

1. To perform random sampling, I used the Data Analysis function under the Data tab. Once I clicked on Data Analysis I chose the Sampling function. I then chose the Input Range of data to be random sampled. I checked the Random Sampling Method and input the number of random samples to be selected, 20. I then chose Output Range in the Output Options area of the Sampling box and selected an area on my Excel document to display the output. I clicked OK and the random samples were automatically chosen and displayed in the appropriate chosen location on my Excel document. The Sampling method in the Data Analysis add-on pack is very important to use when truly random samples need to be taken from a group of data for analysis. 2.

Part 2. Cereal and Fiber Type

Fiber Type| Frequency| % fiber|
High Fiber| 22| 26%|
Medium Fiber| 29| 35%|
Low Fiber| 33| 39%|
Total| 84| 100%|

Part 3. Milk Production

1. The sample mean of the data is 2270.54 lbs. of milk production.

2. The sample standard deviation of the milk production is 653.1822.

3.
Milk Production|
Class Limits|  |  | Cumulative|
Lower| Upper| Midpoint| Frequency| Frequency|
1147| 1646| 1396.5| 7| 7|
1647| 2146| 1896.5| 15| 22|
2147| 2646| 2396.5| 13| 35|
2647| 3146| 2896.5| 11| 46|
3147| 3646| 3396.5| 3| 49|
3647| 4146| 3896.5| 0| 49|
4147| 4646| 4396.5| 1| 50|

4.

The data does appear to be bell shaped because the data is high in the center, low on the sides and has slightly bell flared edges.

5. The Empirical Rule states that as long as 68% of the data is within 1 standard deviation, 95% of the data is within 2 standard deviations and 99.7% of the data is within 3 standard deviations. Upon calculation, using a Standard Deviation of 653.1822 and a Mean of 2270.54, I have...

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