Question

4. A field recently fertilized with manure is believed to have caused excessive levels of nitrate in an adjacent pond. Twenty

Nitrate (mg/L) 1 Nitrate (mg/L) 25 29 34 21 38 26 38 83 37 38 34 34 26 28 24 24 26 10 12 13 14 15 16 17 18 19 20 21 32 29 28

pls help!!

0 0
Add a comment Improve this question Transcribed image text
Answer #1

Firstly arrange the data in ascending form as follows :

21
22
22
24
24
25
26
26
26
28
28
29
29
31
32
33
34
34
34
37
37
38
38
38

83

The sample mean is 31.96 and standard deviation is 11.95 (pls note degree of freedom is 24)

For Dixon ration calculate the ratio R22 = Xn - X n-2 / Xn - X3 = 83-38 / 83-22 = 0.73

The critical value for this ratio is 0.46 at 5% level of significance. As 0.73 > 0.46 the null hypothesis is rejected that there is no outlier. 83 is thus the outlier.

For the Grubb test calculate G = Max I X - Sample Mean I / Standard deviation

The maximum value that is got is 4.27113 when X is 83. The critical value for this is 2.82 when n=25.

As 4.27 > 2.82, the null hypothesis is rejected.

NB

The data needs to be checked for normality first before these tests can be done. I have assumed normality.

Add a comment
Know the answer?
Add Answer to:
pls help!! 4. A field recently fertilized with manure is believed to have caused excessive levels...
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for? Ask your own homework help question. Our experts will answer your question WITHIN MINUTES for Free.
Similar Homework Help Questions
ADVERTISEMENT
Free Homework Help App
Download From Google Play
Scan Your Homework
to Get Instant Free Answers
Need Online Homework Help?
Ask a Question
Get Answers For Free
Most questions answered within 3 hours.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT