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| Suppse you want to find the normal heart rate of your friend Roxanne. Heart rate is the number of times a heart beats in one minute. | |||||||||||
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You can feel heartbeats if you hold your fingers on the side of your neck or the inside of your wrist. The beats you feel are called your pulse. | You take Roxanne's pulse and count 92 beats in one minute. But you can't say for sure that this is her normal heart rate. Maybe you counted wrong or read your watch incorrectly. | |||||||||
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| Roxanne's average heart rate was 91. An average of the trials gives you a more accurate idea of Roxanne's heart rate than the results of any single trial. (See data chart below) | |||||||||||
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| How can you be sure of Roxanne's normal heart rate? You can do more trials. A trial is a repeat of a test or an observation. The more trials you do, the more you can trust the data that you collect. | |||||||||||
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| Suppose you decide to do six trials. You record the data in a table like this one.
The six trials tell you that Roxanne's normal heart rate falls in a range between 89 and 93 beats per minute. You can also find Roxanne's average heart rate. First, add the heart rates you found in each trial. 92+89+92+90+93+90=546 Then divide by the numbers of trials 546 divided by 6 equals 91 |
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