In a recent year the magnitudes (Richter scale) of 10,594 earthquakes were recor

Question

In a recent year the magnitudes (Richter scale) of 10,594 earthquakes were recorded. The mean is 1.274 and the standard deviation is 0.59. Consider the magnitudes that are unusual. What are the magnitudes that separate the unusual magnitudes from those that are usual? (Consider a value to be unusual if its z score is less than - 2 or greater than 2.) What are the magnitudes that separate the unusual magnitudes from those that are usual? The lower bound earthquake magnitude is The higher bound earthquake magnitude is

Explanation / Answer

          
Thus, the z score corresponding to the left endpoint, by table/technology, is          
          
z1 =    -2      
By symmetry,          
z2 =    2      
          
As          
          
u = mean =    1.274      
s = standard deviation =    0.59      
          
Then          
          
x1 = u + z1*s =    0.094   [ANSWER, LOWER BOUND]  
x2 = u + z2*s =    2.454   [ANSWER, HIGHER BOUND]  

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.