The systolic blood pressure of 16 students was measured before a test. The blood pressure from...

The systolic blood pressure of 16 students was measured before a test. The blood pressure from this sample averaged 165, with a standard deviation of 40.

a) Compute the approximate 95% confidence interval for mean systolic blood pressure, and make a sketch illustrating these confidence intervals

b) If a mean blood pressure above 130 is considered “stressed”, what do your calculations show regarding the probability that the observed mean is above the “stressed” level.

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Expert Solution

Level of Significance ,    α =    0.05
sample std dev ,    s =    40
Sample Size ,   n =    16
Sample Mean,    x̅ =   165

a) degree of freedom=   DF=n-1=   15
't value='   tα/2=   2.1314   [Excel formula =t.inv(α/2,df) ]

Standard Error , SE =   s/√n =   10.0000
margin of error ,   E=t*SE =   21.3145
95% confidence interval is
Interval Lower Limit=   x̅ - E =    143.6855
Interval Upper Limit=   x̅ + E =    186.3145

we are 95% confident that true mean systolic blood pressure lies within confidence interval.

confidence interval is above 130,so, observed mean is above stressed level

orchestra answered 1 year ago

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