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An article in the ASCE Journal of Energy Engineering (1999, Vol. 125, pp. 59-75)

ID: 3150168 • Letter: A

Question

An article in the ASCE Journal of Energy Engineering (1999, Vol. 125, pp. 59-75) describes a study of the thermal inertia properties of autoclaved aerated concrete use; as a building material. Five samples of the material were tested in a structure, and the average interior temperatures (degree C) reported were as follows: 23.01, 22.22, 22.04, 22.6. and 22.59. Test the hypothesis H_0: mu = 22.5 versus H_1: mu notequalto 22.5, using a = 0.05. Compute the test statistic, - 0.0237 0.0237 0.01958 -0.01958 What region supports H_0? -2.132

Explanation / Answer

Hi! I used these data:

23.01
22.22
22.04
22.62
22.59

If some data are cut from this picture, please resubmit this question together with the data. That way we can continue helping you! Thanks!

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A)

Formulating the null and alternative hypotheses,              
              
Ho:   u   =   22.5  
Ha:    u   =/   22.5  
              
As we can see, this is a    two   tailed test.  
Getting the test statistic, as              
              
X = sample mean =    22.496          
uo = hypothesized mean =    22.5          
n = sample size =    5          
s = standard deviation =    0.378325257          
              
Thus, t = (X - uo) * sqrt(n) / s =    -0.023641752   [ANSWER, TEST STATISTIC]

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b)
  
              
Thus, getting the critical t,              

df = n - 1 =    4          

tcrit =    +/-   2.776445105      
              
Hence, the region is

OPTION C: -2.776 < t < 2.776 [ANSWER]

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c)      
              
Also, the p value is, as this is two tailed,              
              
p =    0.98227075   [ANSWER]      

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d)
              
As P > 0.05, we   FAIL TO REJECT THE NULL HYPOTHESIS.  

Hence, there is no significant evidence that the mean temperature is not 22.5 degrees Celcius at 0.05 level. [CONCLUSION]      

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