Inequality with OR: We use OR when you have two or more cases that could or not happen at the same time, for example with inequalities when you have an OR you use the union of the sets given by the inequalities. for example if we have the following two inequalities

it will represent the union of the set of numbers that are greater than one with the set of the numbers that are less than zero.
Inequality with AND: We use AND when you need that all the conditions holds at the same time (here is not accepted that only one holds) for example with inequalities when you have AND you need to use the intersection of the sets given by the inequalities. For example:

will represent the intersection of the set of number that are greater than two and less than ten AT THE SAME TIME
15.75:14=9:8
3:1.875=2:1.25
Hope this helps, although I am not a 100% sure it is correct :)
Answer:
-4/3
Step-by-step explanation:
Answer:
Step-by-step explanation:
Hello!
The experiment was designed to proof if the physiological blind spot can be reduced with eye training.
One sample of n people was taken and the physiological blind spot was measured. After that, the people selected underwent 3 weeks of eye training and their physiological blind spot was measured again. At the end of the experiment you have two sets of data for the sample, let's call X₁: physiological blind spot of one person before taking eye training", the measurements were taken before the training will correspond to this variable, and X₂: physiological blind spot of one person after three weeks of eye training" the second measurements correspond to this variable.
In this type of situation, where only one sample is taken and both variables are measured to the same observational unit (there is a pair of observations for each person), the observations are dependant and the corresponding test is the paired samples t-test.
To analyze the information you need to create a new variable, usually symbolized as Xd, that will be the difference between X₁ and X₂.
So your response variable would be
Xd: "Difference between a physiological blind spot of one person before taking eye training and physiological blind spot of after three weeks of eye training"
Xd= X₁ - X₂
The study parameter will be the mean of the variable "difference" μd.
I hope it helps!