Normal distribution

Question 1

what is normal distribution?

Answer 1

The one that has bell shape, is for continuous variable.

numeral continuous variables=ranges

Question 2

what are the methods used for probe that our dat is enarly normal distributed?

Answer 2

• plot a normal distributed curve and a histogram o our data (matching their mean and sd)
• Q-Q plot for “quantile-quantile”
• Using the repeat function and compared it with other normalized data

Question 3

how a q-q plot works?

Answer 3

A data set that is nearly normal will result in a probability plot where the points closely follow the line. Any deviations from normality leads to deviations of these points from the line.

Question 4

what is the z-score?

Answer 4

The Z-score of an observation is the number of standard deviations σ it falls above or below the mean, providing us normal probabilities, since their mean and sd msut match with normalized data.

Question 5

when is the z-score used?

Answer 5

Once we decide that a random variable is approximately normal,

Question 6

how is z-score equated?

Answer 6

The Z-score for an observation x that follows a distribution with mean μ and standard deviation σ
using:

Z=(x−μ)/σ

the probability always give us the area under the curve beore the x