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1.
 
The Liquid Chlorine: No 18 Hal 342-343
The liquid chlorine added to swimming pools to combat algae has a relatively short shelf life before it loses its effectiveness. Records indicate that the mean shelf life of a 5-gallon jug of chlorine is
2,160 hours
 (90 days). As an experiment, Holdlonger was added to the chlorine to find whether it would
increase
 the shelf life. A sample of nine jugs of chlorine had these shelf lives (in hours): At the
.025
 level, has Holdlonger increased the shelf life of the chlorine? Estimate the p-value.
Jawab: Step 1:
 State the null hypothesis and the alternate hypothesis.
 
H0 : µ
 2.160 H1 : µ > 2.160 (Kata kunci:
increase
)
Step 2:
 Select the level of significance.
 = 0,025 seperti yang tertera di soal df = n-1 = 9-1 = 8 Critical t value = 2,306
Step 3:
 Select the test statistic. Menggunakan tabel t. Hal ini diketahui karena n < 30 dan
 tidak diketahui.
Step 4:
 Formulate the decision rule. Ho ditolak jika t > 2,306
 
2.159 2.170 2.180 2.179 2.160 2.167 2.171 2.181 2.185 
 
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Step 5:
Make a decision and interpret the result.
X bar
 
=

 =

 
= 2.172 S
=
 


 =
 

 
= 9,382311963 t
=
   √ 
 =
    √ 
 
= 3,97912
 
NoX(X - Xbar)^2
12.159 18122.170 632.180 5742.179 4352.160 15562.167 3072.171 282.181 7392.185 158
Total19.552 704
 
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Keputusan =
Ho ditolak 
. Hal ini disebabkan t value sebesar 3,97912 berada di wilayah Ho ditolak. Kesimpulan = Holdlonger
meningkatkan
 umur penyimpanan klorin.
Step 6:
Estimate the p-value. P value dari 3,97912 berada pada
line
df 8, diantara significant level 0,005 dan 0,0005. Dapat disimpulkan bahwa P value kurang dari 0,005.
2.
 
Hugger Polls: No 20 Hal 343
Hugger Polls contends that an agent conducts a mean of
53
 in-depth home surveys every week. A streamlined survey form has been introduced, and Hugger wants to evaluate its effectiveness. The number of in-depth surveys conducted during a week by a random sample of 15 agents are: At the
.05
 level of significance, can we conclude that the mean number of interviews conducted by the agents is
more than
53 per week? Estimate the  p-value.
Jawab: Step 1:
 State the null hypothesis and the alternate hypothesis.
 
H0 : µ
 53 H1 : µ > 53 (Kata kunci:
more than
)
Step 2:
 Select the level of significance.
 = 0,05 seperti yang tertera di soal df = n-1 = 15-1 = 14 Critical t value = 1,761
 
535750555854605259626060515956
 
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Step 3:
 Select the test statistic. Menggunakan tabel t. Hal ini diketahui karena n < 30 dan
 tidak diketahui.
Step 4:
 Formulate the decision rule. Ho ditolak jika t > 1,761
Step 5:
Make a decision and interpret the result.
X bar
 
=

 =

 
= 56
NoX(X - Xbar)^2
1 53 122 57 03 50 414 55 25 58 36 54 67 60 138 52 199 59 710 62 3111 60 1312 60 1313 51 2914 59 715 56 0
Total846196
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