SOLUTION: Dr. Susan Breuner is an industrial psychologist. She is studying stress among executives amount internet companies. She has developed a questionnaire that she believes measures str

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Question 670666: Dr. Susan Breuner is an industrial psychologist. She is studying stress among executives amount internet companies. She has developed a questionnaire that she believes measures stress. A score of 80 indicates stress at a dangerous level. A random sample of 15 executives revealed the following stress level scores:
90 78 83 90 78 99 97 90 97 90 93 94 100 75 84
a) Find the sample mean and sample standard deviation.
b) Construct a 95% confidence interval for the population mean.
c) Can you conclude that internet executives have a mean stress level in the dangerous level and why?
Please show all work, calculations, and formulas! Thank you!
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

A score of 80 indicates stress at a dangerous level

90 78 83 90 78 99 97 90 97 90 93 94 100 75 84 , m+=+89.2  , s+=+7.98

95% confidence level.  Degree of freedom = 14,   +z+=+2.14

ME =+2.14%287.98%2Fsqrt%2815%29%29 

  89.2 - ME < mu < 89.2 + ME

z+=+%2889.2-80%29%2F%287.98%2Fsqrt%2815%29%29 = 4.46,  z = 4.46, Yes, dangerous