statistical tests

Question 1

What are the three types of statistical tests

Answer 1

chi-squared
student T test
the correlation coefficient

Question 2

what does chi-squared measure

Answer 2

it counts the frequency/how many individuals are in a category.

It investigates a difference between the observed unexpected numbers

Question 3

What does it mean if the chi squared value is greater than the critical value

Answer 3

if the calculated value is greater than the critical value, that is a less than 5% probability that the difference between the observed and expected values is due to chance. This means that we reject the null hypothesis that there is a significant difference between the number of x variable and y variable.

Question 4

What happens if the probability value is equal to the critical value in the chi squared

Answer 4

We reject the null hypothesis as there is a 5% probability that the difference in results is due to chance

Question 5

How are biology statistical test different to maths statistical tests

Answer 5

In biology if the calculator value is greater than the critical value we reject the null hypothesis whereas in maths it’s the opposite

Question 6

How do you workout the degrees of freedom in chi squared

Answer 6

you have the number of variables take away one

Question 7

What is the student T test and what does it test for

Answer 7

Tests for continuous data (taking measurements) it investigates a difference between two means

Question 8

How do you workout the degrees of freedom in a student T test

Answer 8

(The number of data points in the first sample + the number of data points in the second sample) -2

Question 9

What is an unpaired student T test

Answer 9

Wehere both sets of data are independent and come from different individuals

Question 10

What is a paired student T test

Answer 10

we are both sets of data come from the same individual or group.

but the sets of data can be collected at different times

Both groups have the same sample size

Question 11

What happens if the student t-test value is greater than the critical value

Answer 11

H0: there is no significant difference between the mean of one set of data and another

We reject the null hypothesis above. There is a less than 5% probability that the difference between the means is due to chance, therefore we reject the null hypothesis.

Question 12

What is the correlation coefficient and what does it test for

Answer 12

it tests continuous data, taking measurements/looking for an association/correlation between two measurements

Question 13

What numbers can the correlation coefficient be between

Answer 13

-1 & 1

Question 14

What does a positive value indicate in the correlation coefficient

Answer 14

Positive value indicates a positive correlation

Question 15

What does a negative value represent in the correlation coefficient

Answer 15

A negative value represents a negative correlation

Question 16

What does a value close to 0 represent in the correlation coefficient

Answer 16

A value close to 0 indicates little correlation between the two sets of data. Or it could indicate no correlation

Question 17

What is another name that can be given to the correlation coefficient

Answer 17

The spearman’s rank correlation coefficient

Question 18

What happens if the Spearman’s rank correlation coefficient is less than the critical value

Answer 18

H0: There will be no significant correlation between temperature and enzyme rate of reaction

There is a greater than 5% probability that the correlation is due to chance. Therefore we accept the null hypothesis. and increasing the temperature does not always result in an increase in the rate of enzyme reaction

Question 19

What is a good way to remember whether a statistical test a significant or not

Answer 19

Pogba‘s left leg can shoot
PL LC S

if the probability/p value is less than the significance level then there is a less than (5%) probability that the difference in the two means is due to chance. this means that the difference between the two means is significant.