Statistical Tests

A biologist wanted to investigate the relationship between temperature and rate of pigment leakage from beetroot.

Their null hypothesis read 'there is no correlation between the temperature and rate of pigment leakage'

Which stats test should they use to process their data?

• unpaired t-test

• paired t-test

• Spearman's rank correlation

• chi-squared

The biologist obtained a calculated value of 0.98. Their critical value was 0.65.

What do they do with their null hypothesis?

• accept

• reject

Chi square is looking for statistical significance between

• means

• frequencies

• medians

What is "there is no difference in the means of the two groups?"

• alternative hypothesis for chi square

• null hypothesis for t test

• null hypothesis for Spearman's rank correlation

What is "there is no difference in the frequency of eye colour in the population' ?

• null hypothesis for t test

• alternative hypothesis for t test

• null hypothesis for chi square

• alternative hypothesis for chi square

A group of students had their reaction times measured before and after a bag of haribo (a mini one).

Which stats test should be used to compare reaction times before and after the haribo?

• chi squared

• unpaired t-test

• paired t-test

• Spearman's Rank correlation

In an unpaired t-test, how do you work out the degrees of freedom?

(n is the number of sets of data)

• n - 1

• (N₁ + N₂) - 2

• n + 1

• 2n

In a paired t-test, how do you work out the degrees of freedom?

(n is the number of sets of data)

• n - 1

• (N₁ + N₂) - 2

• n + 1

• 2n

Calculate the standard deviation for this set of data:

Length of branches in m

4, 8, 8, 8, 10, 10

• 8

• 2.19

• 4.8

• no idea

What is the purpose of the t-tests?

• to look for correlations between mean values

• to compare mean values

• to compare observed and expected frequencies