statistical tests / data

Question 1

Spearman’s Rank Correlation Coefficient

Answer 1

Find correlation between two measurements

Null Hypothesis:
-NO significant correlation between variable 1 and variable 2

To reject null hypothesis, P<0.05
(95% confidence)
Rs >= critical value

Question 2

Standard Error and 95% Confidence Limits

Answer 2

Measures how close sample mean and population(actual) mean are

Null Hypothesis:
-No significant difference between two means

Closer to 0 = closer to actual mean

95% confidence limit
-Range within which you are 95% confident the true mean lies

Question 3

Chi Squared

Answer 3

Only statistical test for discrete data (frequencies)

Compares expected frequencies to observed frequencies

To reject null hypothesis, P<0.05
Chi^2 >= critical value

Question 4

why straight lines used to join points instead of a curve of best fit

Answer 4

cannot be certain of intermediate values