Chem 315 Quantitative Analysis In-Class/Take Home 1 DUE In Class: Tuesday 2/6/18

Question

Chem 315 Quantitative Analysis In-Class/Take Home 1 DUE In Class: Tuesday 2/6/18 2.5 points) The concentration of ozone (0s) in the atmosphere (in pb) in Fullerton was measured at two different times. Eac the two measurements statistically different at the 95% confidence level? In other words, did the ozone concentration increase by a statistically significant amount (>95% confidence level) between 12:00 pm and 4:00 pm? measurement was made in triplicate, giving the following results. Are 12:00 pm (ppb) 4:00 pm (ppb) 41.2 40.5 42.5 41.40 1.0149 43.8 43.5 42.9 43.40 0.4583

Explanation / Answer

Lets denote the data for 12 pm by subscript 1 and for 4 pm by subscript 2.

Data given:

m1 = 41.4, S1 = 1.0149, n1 = 3

m2 = 43.4, S2 = 0.4583, n2 = 3

Calculating standard error:

SE = (S12/n1 + S22/n2)0.5 = (1.01492/3 + 0.45832/3)0.5 = 0.643

Calculating test statistic:

t = (m2-m1)/SE = (43.4-41.4)/0.643 = 3.11

Degrees of freedom, df = 2

The corresponding p-value for this t-score is:

p = 0.0448

Since the p-value is smaller than the significance level of 0.05, thus the difference is significant at this level.

Thus the ozone conc increased significantly.

Hope this helps !

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

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