9 Use the data in the MS Excel spreadsheet see below to tes

9. Use the data in the MS Excel spreadsheet (see below ) to test the hypothesis at = 0.05:

H0: µ = 20

Ha: µ < 20

a. Sample mean: ______________

b. Sample standard deviation: ________________

c. Test statistic: _______________

d. Rejection region: ____________

e. Decision (reject H0 or do no reject HO):

Excel Spreadsheet:

15.6

19.4

Solution

a)

Using technology,

X = sample mean =    17.57   [ANSWER]

********************

b)      
  
s = standard deviation =    2.952230795   [ANSWER]

********************

c)  
              
              
Getting the test statistic, as              
              
X = sample mean =    17.57          
uo = hypothesized mean =    20          
n = sample size =    10          
s = standard deviation =    2.952230795          
              
Thus, t = (X - uo) * sqrt(n) / s =    -2.602890915 [ANSWER]

************************

d)          

Thus, getting the critical t,              
df = n - 1 =    9          
tcrit =    -   1.833112933      

Thus, reject Ho when t < -1.8331. [ANSWER]

************************

e)

As t < -1.8331, we   REJECT HO.
************************