Stats

Question 1

Define standard deviation

Answer 1

Spread of data around the mean

Question 2

When is a difference significant?

Answer 2

When standard deviations do not overlap

Question 3

When do you use chi squared?

Answer 3

When looking at the difference in frequencies in different categories

Question 4

How would you write a null hypothesis for chi squared?

Answer 4

There is no significant difference in the number of _____ in _______ than ______

Question 5

What do you do if your value is larger than or equal to the critical value?

Answer 5

• There is a less than or equal to 5% probability that the difference is due to chance
• Reject the null hypothesis
• There is a significant difference

Question 6

What does it mean if your value is less than the critical value?

Answer 6

• There is a greater than 5% probability that the result is due to chance
• Accept the null hypothesis
• There is no significant difference

Question 7

How do you find degrees of freedom for chi squared?

Answer 7

number of categories -1

Question 8

When do you use the student t test?

Answer 8

When finding if there is a significant difference in means of data sets

Question 9

What would the null hypothesis for a student t test be?

Answer 9

There is no significant difference in the means of ______ and _______

Question 10

How do you find the degrees of freedom for student t test?

Answer 10

(n1+n2)-2

Question 11

When do you use spearman’s rank?

Answer 11

When looking for correlations and associations

Question 12

What would a null hypothesis for spearman’s rank be?

Answer 12

There is no significant correlation between ________ and _______

Question 13

How do you know what the value from spearman’s rank means?

Answer 13

• -ve = negative correlation –> closer to -1 - stronger the correlation
• +ve = positive correlation –> closer to +1 - stronger correlation
• 0 = no correlation
• Still use critical value