1st year stats, empirical rule- range of values

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Homework Help Overview

The discussion revolves around a first-year statistics problem involving the empirical rule and the analysis of a given data set. The original poster presents their calculations, including mean, variance, and standard deviation, and questions the applicability of the empirical rule to their data set.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to apply the empirical rule to their data, questioning whether the data's distribution can be considered normal. They seek clarification on how to determine the range of values for 68% of the data based on their calculations.

Discussion Status

Some participants provide guidance on the empirical rule, indicating that if the data were normal, approximately 68% would lie within one standard deviation of the mean. The original poster later calculates the specific range and attempts to determine the actual percentage of data within that range, leading to further exploration of the data set.

Contextual Notes

The original poster expresses confusion regarding the nature of their data set and its conformity to a normal distribution, which is central to the application of the empirical rule. There is an acknowledgment of the potential for an incorrect answer based on the assumption of normality.

m0286
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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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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.
 
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.
 
Yes, that's correct.
 

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