1st year stats, empirical rule- range of values

The question is asking for the percentage of data that falls within the range of values that is within 1 standard deviation from the mean, which in this case includes the values 26, 32, 33, 38, 45, and 53. In summary, the data set provided has a mean of 42.182, sample variance of 272.147, range of 43, percentile rank of 59th for the value 45, and value corresponding to the 80th percentile of 63. According to the empirical rule, if the data is normal, approximately 68% of the data will lie within 1 standard deviation of the mean, which in this case includes the values 26, 32,
  • #1
m0286
63
0
Hello
I am taking 1st year stats at university, and I have lab questions I am supposed to answer. I am VERY confused.
My data set is:
53, 33, 25, 63,26, 64, 32, 21, 45, 64, 38
I calculated the mean:42.182
the sample variance:272.147
The range:43
The percentile rank of the data value 45: 59th
The value corresponding to the 80th percentile:63
Q1:26
Q2:38
Q3:63
Outliers: none
Standard deviation: 16.497
Now I am asked: according to the empirical rule, if the above data is normal find the range of values in which approximately 68% of the data will lie. I know the empirical rule applies only to bellcurved graphs... but this would not produce a bell curve correct? So would there be an answer?

Then they ask: What is the actual percentage of the data that lie in your interval from above.?

Any help is appreciated thanks!
 
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  • #2
You should know that if the data is normal then about 68% of the data lies within 1 standard deviation of the mean. They expect an incorrect answer for the first part--they are saying, what if it were normal, then what would the answer be.
 
  • #3
THANKS! I realize now what they are asking and got the answer:

mean-standard deviation=25.685
mean+standard deviation= 58.679

So for the next part: What is the actual percentage of the data that lies in the intervals from previous question.

So would I do, which of these intervals: 22 25 26 32 33 38 45 53 63 64 64 will lie between 25.685 and 58.679??
which is 26, 32, 33, 38, 45, 53
so: 6/11 fall within those intervals, so 6/11 * 100 = 54.54% of the data lie between these intervals.
THANKS again.
 
  • #4
Yes, that's correct.
 

FAQ: 1st year stats, empirical rule- range of values

What is the empirical rule in statistics?

The empirical rule, also known as the 68-95-99.7 rule, states that for a normal distribution, approximately 68% of the data falls within one standard deviation of the mean, 95% falls within two standard deviations, and 99.7% falls within three standard deviations.

How is the empirical rule used in data analysis?

The empirical rule is used to determine the range of values that are considered "normal" in a data set. It helps to identify outliers and determine the probability of a certain value occurring within a given range.

What is the significance of the range of values in the empirical rule?

The range of values in the empirical rule helps to understand the spread of the data and how closely it conforms to a normal distribution. It also helps to identify potential errors or unusual patterns in the data.

Can the empirical rule be applied to any data set?

The empirical rule can be applied to data sets that follow a normal distribution. This means that the data is bell-shaped and symmetric around the mean. If the data does not follow a normal distribution, the empirical rule may not accurately describe the data.

How does the empirical rule relate to the concept of standard deviation?

The empirical rule is based on the concept of standard deviation, which is a measure of how much the data values deviate from the mean. The three ranges in the empirical rule are determined by multiplying the standard deviation by 1, 2, and 3, respectively.

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