Question

In: Statistics and Probability

or a sample group of 25 men subjected to a stress situation, the meannumber of heartbeats...

or a sample group of 25 men subjected to a stress situation, the meannumber of heartbeats per minute was 76, and the standard deviation was 6.

Find the95% confidence interval of the true mean.Write a conclusion for the confidence interval.Round to 3 decimal places.

Solutions

Expert Solution


Solution :

Given that,

= 76

s = 6

n = 25

Degrees of freedom = df = n - 1 = 25 - 1 = 24

At 95% confidence level the t is ,

  = 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

t /2,df = t0.025,24 =2.797  

Margin of error = E = t/2,df * (s /n)

= 2.797 * (6 / 25)

= 2.48

Margin of error = 2.48

The 95% confidence interval estimate of the population mean is,

- E <  < + E

76 - 2.48 < < 76 + 2.48

73.52 < < 78.48

(73.52, 78.48 )


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