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The instructions are as follows: -Write all given values -State the null and alt

ID: 3379089 • Letter: T

Question

The instructions are as follows:

-Write all given values

-State the null and alternative hypotheses

-Determine the level of significance,

-Determine the approproiate test statistic to be used and compute

-Determine the critical region and find its value

-Write your decision whether to reject or do not reject the null hypothesis, state your interpretation

The average height of females in the freshman class of a certain college has historically been 162.5 centimeters with a standard deviation of 6.9 centimeters. Is there reason to believe that there has been a change in the average height if a random sample of 50 females in the present freshman class has an average height of 165.2 centimeters? Use 0.05 level of significance. (13pts) 1.

Explanation / Answer

Formulating the null and alternative hypotheses,              
              
Ho:   u   =   162.5  
Ha:    u   =/   162.5   [ANSWER, HYPOTHESES]

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As we can see, this is a    two   tailed test.      
              
Thus, getting the critical z, as alpha =    0.05   [SIGNIFICANCE]

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Getting the test statistic, as              
              
X = sample mean =    165.2          
uo = hypothesized mean =    162.5          
n = sample size =    50          
s = standard deviation =    6.9          
              
Thus, z = (X - uo) * sqrt(n) / s =    2.766939579   [ANSWER, TEST STATISTIC]

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alpha/2 =    0.025          
zcrit =    +/-   1.959963985      
              
Thus, the critical region is z < -1.959963985 or z > 1.959963985. [CRITICAL REGION]

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As z > 1.959963985, we   REJECT THE NULL HYPOTHESIS.  

Thus, there is significant evidence that there is a change in the avergae height of females in the freshman class. [CONCLUSION]      

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