Probability: Given the Mean and Standard deviation

  • Thread starter Nikki10
  • Start date
  • #1
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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 dont understand the concept
 

Answers and Replies

  • #2
912
19
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...
 
  • #3
9
0
thank you
 

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