The Journal of Hazardous Materialt (jams published the results ot a study of the

Question

The Journal of Hazardous Materialt (jams published the results ot a study of the chemicul properties of three different types of organic solvents wed to clean metal pay ts arom atics (hlor oalkanes, esters One variable studied was sorption rate measured as Mule percentages. Independent Samples of solvents frym each Me were tested and their sorption rwes we c recorded Suppose we just want to see if there is a difference between jus the aromal s ond esters sum le 10 butches of solvents f m buth types. We find that the man and standard deviation are l and l.14 The mean and standard deviation of the esters are 13 and 1.13. Test whether there is a difference belween the mean sorption rude ot the two solvents d the .05 significance leur). Givena P lol: 02S

Explanation / Answer

Answer to question# 1)

10 samples from each type are analysed

Thus n1 = n2 = 10

For group I:

Mean (x1 bar) = 1.74

Standard deviation (s1) = 1.14

For group II:

Mean (x2 bar) = 2.37

Standard deviation (s2) = 1.23

.

We got alpha = 0.05

df = n1 + n2 - 2 = 10+10-2 = 18

.

Hypothesis:

Ho: the two groups have same mean

Ha: the two groups have different means

[Hence it is two tailed test]

.

The value of test statistic is :

t = (x2 bar - x1bar) / (sqrt(s1^2/10 + s2^2/10))

t = (2.37-1.74) / sqrt(1.23^2/10 + 1.14^2/10)

0.15129 +0.12996 =0.28125 = 0.5303

t = 0.63 / 0.5303

t = 1.19

.

Pvalue: for two tailed t test with t = 1.19 and df = 18 , we get the pvalue as :

p value = 0.2495

.

Inference:

Since the P value 0.2495 > significance level 0.05

We fail to reject the null

.

Conclusion: Thus we conclude that the two groups have same mean

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.