Statistics

Question 1

what is the null hypothesis for chi squared?

Answer 1

• there is no difference between observed and expected FREQUENCIES

Question 2

what is the null hypothesis for spearman’s rank (correlation co-efficient)?

Answer 2

• there is no correlation between X WITH Y

Question 3

what is the null hypothesis for student’s t-test?

Answer 3

• there is no significant difference between the MEANS of X with Y

Question 4

what are the degrees of freedom for chi squared?

Answer 4

• number of categories - 1

Question 5

what are the degrees of freedom for spearman’s rank?

Answer 5

• number of pairs

Question 6

what are the degrees of freedom for the t-test?

Answer 6

• (n1 + n2) - 2

Question 7

what can we conclude if P < 0.05?

Answer 7

• if there is less than 5% probability the difference is due to chance
• REJECT the null hypothesis
• results are SIGNIFICANT
• not due to chance

Question 8

what can we conclude if P > 0.05?

Answer 8

• if there is more than 5% probability the difference is due to chance
• ACCEPT the null hypothesis
• results are NOT significant
• due to chance

Question 9

when do you use chi squared?

Answer 9

• categorical data when COMPARING FREQUENCIES

Question 10

when do you use spearman’s rank?

Answer 10

• interval/ordinal data when looking for ASSOCIATIONS/CORRELATIONS between two variables

Question 11

when do you use t-test?

Answer 11

• paired data when COMPARING MEANS