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Please answer them all with step by step solutions The weekly income of a large

ID: 3134557 • Letter: P

Question

Please answer them all with step by step solutions

The weekly income of a large group of middle managers are normally distributed with the mean of $800 and a standard deviation of $45. what is the probability of finding a middle manager with a weekly income of between S840 and $900, what is the percentage of middle managers that earn more the $905 what is the percentage of middle managers that earn less than $905 what is the probability of finding a middle manager with weekly income of between $ 750 and $ 850 what is the probability of finding a middle manager with weekly income of between $ 750 and 790 above what income would the top 10% managers earn below what income would the lowest 10% of managers earn

Explanation / Answer

a)

We first get the z score for the two values. As z = (x - u) / s, then as          
x1 = lower bound =    840      
x2 = upper bound =    900      
u = mean =    800      
          
s = standard deviation =    45      
          
Thus, the two z scores are          
          
z1 = lower z score = (x1 - u)/s =    0.888888889      
z2 = upper z score = (x2 - u) / s =    2.222222222      
          
Using table/technology, the left tailed areas between these z scores is          
          
P(z < z1) =    0.812968601      
P(z < z2) =    0.986865854      
          
Thus, the area between them, by subtracting these areas, is          
          
P(z1 < z < z2) =    0.173897253   [ANSWER]

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B)

We first get the z score for the critical value. As z = (x - u) / s, then as          
          
x = critical value =    905      
u = mean =    800      
          
s = standard deviation =    45      
          
Thus,          
          
z = (x - u) / s =    2.333333333      
          
Thus, using a table/technology, the right tailed area of this is          
          
P(z >   2.333333333   ) =    0.009815329 [ANSWER]

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c)

We first get the z score for the critical value. As z = (x - u) / s, then as          
          
x = critical value =    905      
u = mean =    800      
          
s = standard deviation =    45      
          
Thus,          
          
z = (x - u) / s =    2.333333333      
          
Thus, using a table/technology, the right tailed area of this is          
          
P(z >   2.333333333   ) =    0.009815329 [ANSWER]

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d)

We first get the z score for the two values. As z = (x - u) / s, then as          
x1 = lower bound =    750      
x2 = upper bound =    850      
u = mean =    800      
          
s = standard deviation =    45      
          
Thus, the two z scores are          
          
z1 = lower z score = (x1 - u)/s =    -1.111111111      
z2 = upper z score = (x2 - u) / s =    1.111111111      
          
Using table/technology, the left tailed areas between these z scores is          
          
P(z < z1) =    0.133260263      
P(z < z2) =    0.866739737      
          
Thus, the area between them, by subtracting these areas, is          
          
P(z1 < z < z2) =    0.733479474   [ANSWER]  

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