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a2 SNAB BIOLOGY COURSEWORK

help me
can some one tell me what the critical value is for the spearmans rank corellation coefficient?

mine is -0.617489177

first reply gets reps
(edited 13 years ago)
Original post by xshopoholicx
help me
can some one tell me what the critical value is for the spearmans rank corellation coefficient?

mine is -1.68398268

first reply gets reps


because your value is negative it would mean that there is negative correlation between the two variables that you are testing
Reply 2
Original post by xshopoholicx
help me
can some one tell me what the critical value is for the spearmans rank corellation coefficient?

mine is -1.68398268

first reply gets reps


It depends on how many readings you have for a start, it also depends on how accurate you want to be... for A level biology 95% accuracy is usually fine which translates to 0.05 on the tables. Essentially more readings mean a lower score is needed to be significant.

Also spearman's rank values are usually between a range of 1 and -1, you sure you didn't do the test wrong?

Anyhow heres the table for 5%, value on the left being number of results and value on the right being the value needed for spearman's rank to be significant:

5 1.00
6 0.94
7 0.89
8 0.83
9 0.78
10 0.75
11 0.73
12 0.71
13 0.67
14 0.64
15 0.62
16 0.60
17 0.58
18 0.56
19 0.55
20 0.53
21 0.52
22 0.51
23 0.50
24 0.48
25 0.47
26 0.46
27 0.46
28 0.45
29 0.44
30 0.43

If the number is negative still use the table but remember it is a negative correlation and not a positive one.
Reply 3
Original post by Wallam
It depends on how many readings you have for a start, it also depends on how accurate you want to be... for A level biology 95% accuracy is usually fine which translates to 0.05 on the tables. Essentially more readings mean a lower score is needed to be significant.

Also spearman's rank values are usually between a range of 1 and -1, you sure you didn't do the test wrong?

Anyhow heres the table for 5%, value on the left being number of results and value on the right being the value needed for spearman's rank to be significant:

5 1.00
6 0.94
7 0.89
8 0.83
9 0.78
10 0.75
11 0.73
12 0.71
13 0.67
14 0.64
15 0.62
16 0.60
17 0.58
18 0.56
19 0.55
20 0.53
21 0.52
22 0.51
23 0.50
24 0.48
25 0.47
26 0.46
27 0.46
28 0.45
29 0.44
30 0.43

If the number is negative still use the table but remember it is a negative correlation and not a positive one.


sorry the spearmans rank is -0.617489177 and i need it to be a 95% significance
Reply 4
Original post by xshopoholicx
sorry the spearmans rank is -0.617489177 and i need it to be a 95% significance


How many readings did you use?

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