OCR A Level Biology – Stats Test Questions with Verified Answers
1. What is a hypoth- A statement about what you expect your results will show
esis?
2. What is a null hy- A statement that says that there will be no significant ditterent / correlation be-
pothesis? tween the things you are measuring. You want to disprove the null.
3. When would If you wanted to look at ditterences in frequencies between groups. E.g. Is there a
you use the ditterence between the frequency of ditterent bird species at 2 ditterent sites?
Chi-Squared test?
4. Chi-Squared test: If you have a table with just 1 row or column:
how do you work df = number of classes - 1
out degrees of
freedom? If you have a table with more than 1 row:
df = (number of rows - 1) x (number of columns - 1)
5. Chi-Squared test: If your value for Chi-Squared is EQUAL TO or GREATER THAN the critical value, there
how do you know is a significant ditterence and you can REJECT the null hypothesis.
if the data is sig-
nificant?
6. Chi-Squared test:
What is the equa-
tion?
7. When would you Spearman's Rank involves ranking data in order of size. It gives you a numerical
use Spearman's value to tell you the strength and direction of the correlation
Rank?
8. What is a correla- It tells you the strength and direction of a correlation. It can take any value from -1
tion coefficient? to 1.
A negative number shows a negative correlation.
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1. What is a hypoth- A statement about what you expect your results will show
esis?
2. What is a null hy- A statement that says that there will be no significant ditterent / correlation be-
pothesis? tween the things you are measuring. You want to disprove the null.
3. When would If you wanted to look at ditterences in frequencies between groups. E.g. Is there a
you use the ditterence between the frequency of ditterent bird species at 2 ditterent sites?
Chi-Squared test?
4. Chi-Squared test: If you have a table with just 1 row or column:
how do you work df = number of classes - 1
out degrees of
freedom? If you have a table with more than 1 row:
df = (number of rows - 1) x (number of columns - 1)
5. Chi-Squared test: If your value for Chi-Squared is EQUAL TO or GREATER THAN the critical value, there
how do you know is a significant ditterence and you can REJECT the null hypothesis.
if the data is sig-
nificant?
6. Chi-Squared test:
What is the equa-
tion?
7. When would you Spearman's Rank involves ranking data in order of size. It gives you a numerical
use Spearman's value to tell you the strength and direction of the correlation
Rank?
8. What is a correla- It tells you the strength and direction of a correlation. It can take any value from -1
tion coefficient? to 1.
A negative number shows a negative correlation.
1/4
