The first type: H0: μ = μ 0: μ ≠ μ 0 bilateral.
Type Ⅱ: H0: μ≥μ 0: μ < μ 0 Unilateral (left side)
The third type: H0: μ≤ μ 0: μ > μ 0 unilateral (right side)
T-test: when the number of samples n is small, samples are required to be taken from the normal population.
Types of t-test: single sample t-test, independent t-test and paired t-test.
Z test: the number of samples is large, or n is small and population standard deviation is known.
Patty's book uses three types of numbers:
The first category is the figures obtained from the statistical investigation and empirical observation of social and economic phenomena. Due to the limitation of historical conditions, there are few data obtained through strict statistical investigation in the book, and many figures are based on experience.
The second category is the number calculated by some mathematical method. There are three calculation methods:
(1) A calculation method based on a known number or quantity and following a specific relationship.
(2) The method of calculation by theoretical reasoning of numbers.
(3) Calculation method based on average value ".