Stat tests

Question 1

What does standard deviation measure?

Answer 1

it measures the spread of the set of numbers, in effect the average distance of each number from the mean

Question 2

The bigger the standard deviation…

Answer 2

the bigger the spread of numbers

Question 3

The smaller standard deviation…

Answer 3

implies the numbers are close together

Question 4

What can chi-squared be used for?

Answer 4

it can be used to determine the significance of the difference between the observed and expected results

Question 5

What does the O and the E represent in chi-squared?

Answer 5

• the O represents the observed numbers
• the E represents the expected numbers

Question 6

When is the t-test used?

Answer 6

• it is used when looking for the difference between two means and knowing if the difference is ‘significant’ or not
• the sample size needs to be less than 25

Question 7

What does the spearman rank test tell us?

Answer 7

it tells us whether there is a statistically significant correlation between the two measurements from the same sample when there is 5-30 pairs of data

Question 8

What is the Mann-Whitney U test?

Answer 8

• statistical test that is used to test whether there is a significant difference between the medians of two sets of data
• the null hypothesis is tested that the 2 samples come from the same population (there is no significant difference and have the same median)

Question 9

When can the Hardy Weinberg principle be used?

Answer 9

The Hardy Weinberg principle can be used to calculate the allele frequencies, in populations, for traits with dominant and recessive alleles

Question 10

What does the p and the q stand for in the Hardy Weinberg principle?

Answer 10

• p is the dominant allele
• q is the recessive allele