Week 4

Question 1

What are the requirements for a chi-square test and corresponding population variance?

Answer 1

i. The data is a random sample of independent observations
ii. The variable of interest is quantitative and continuous
iii. The measurement scale is interval or ratio
iv. The sampled population is normally distributed
These procedures for variance are based on the assumption that the sampled population is normally distributed, so they should not be applied when the data seems to be extremely non-normal

Question 2

What are the assumptions for the F-test and the corresponding confidence interval for the ratio of 2 population variances?

Answer 2

i. The data consists of two independent random samples of independent observations
ii. The variable of interest is quantitative and continuous
iii. The measurement scale is interval or ratio
iv. The sampled population are normally distributed

Question 3

What are the assumptions for the Z-test? (The Z test is based on large sample procedure i.e. only approximations to the exact procedures are based on the binomial distribution)

Answer 3

i. The data consists of an independent sample of independent observations
ii. The variable of interest is qualitative and has only 2 mutually exclusive but exhaustive categories
iii. The measurement scale is nominal or ordinal
iv. The sampled population is binomially distributed