Wednesday, May 20, 2015

For the following, determine whether the information is accurate, precise, both or neither. During gym class, four students decided to see if they could beat the norm of 45 sit-ups in a minute. The first student did 64 sit-ups, the second did 69, the third did 65, and the fourth did 67. The average score for the 5th grade math test is 89.5. The top 5th graders took the test and scored 89, 93, 91 and 87. Yesterday the temperature was 89 °F, tomorrow it's supposed to be 88 °F and the next day it's supposed to be 90 °F, even though the average for September is only 75 °F degrees! Four friends decided to go out and play horseshoes. They took a picture of their results shown to the right: A local grocery store was holding a contest to see who could most closely guess the number of pennies that they had inside a large jar. The first six people guessed the numbers 735, 209, 390, 300, 1005 and 689. The grocery clerk said the jar actually contains 568 pennies.

Accuracy and precision are two terms used often in science. Accuracy is the closeness of a measurement to the standard or true value. For example, if you measure the length of a 30 foot wall and your reported measurement is 29.99 feet, your measurement is fairly accurate.
Precision is how close the measurements are to each other. For example, you may measure the wall above and obtain the following measurements 24.99 feet, 25 feet, and 25.1 feet. Although your measurements are precise because they are all close together, they are not accurate because they are not close to the 30 foot measurement.
Using these two definitions, let’s take a look at question #1. To determine if the data is accurate we need to decide if the values are close to the standard. The norm is 45, yet the values are 64, 69, 65, and 67. Therefore, this data would not be accurate. To determine precision, we would look at how close the values are to each other. The numbers 64, 69, 65, and 67 are fairly close to each other and therefore would be considered precise. The solution to number one is that the information is precise.
Give the above example and definitions, you should now be able to complete the remaining problems on your own.

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