Probability: Given the Mean and Standard deviation

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SUMMARY

The probability distribution of drug intake among addicts with autoimmune disorders is modeled as a normal distribution N(6.9, 16.81). To find the probability of an addict reporting taking 16 drugs or more, the z-score is calculated as z = (16 - 6.9) / 4.1 = 2.21. The corresponding probability P(z > 16) is determined to be 0.014, indicating a 1.4% chance. The correct formulation for this probability is P[x ≥ 16] = 1 - P[x < 16], confirming the initial calculation.

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  • Understanding of normal distribution and its properties
  • Familiarity with z-scores and their calculation
  • Knowledge of probability tables for normal distributions
  • Basic statistics concepts, including mean and standard deviation
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Nikki10
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Homework Statement



The distribution of a drugs among addicts with autoimmune disorder is N(6.9, 16.81). What is the probability that one of these addicts enters your office and reports taking 16 drugs or more?

The Attempt at a Solution



z = (16-6.9)/4.1 = 2.21
P(z >16) = 0.014 from the table
so P(z > 16) = 0.014 or 1.4%

Is this correct. It seems to simple and maybe I don't understand the concept
 
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your answer is correct but you should have written
[tex]P[x\geq 16]=1-P[x < 16][/tex]

[tex]P[x\geq 16]=1-P[z < 2.21]= 1-0.986[/tex]

so your answer is correct...
 
thank you
 

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