Wes

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0 years, 119 days

MaplePrimes Activity


These are replies submitted by Wes

@mmcdara Hello MMCDARA,

thank you very much for your very interesting and serious study.

Effectively, concerning the SHAPIRO-WILKS test, the obtained results with Maple seems to be false.

It is a very good lesson that imposes on us to verify any soft before using it blindly.

As I confirm to Carl above, I prefer now use my own calculus of the 'ai' coefficients, on Excel.

Have a nice day.

@Wes Hello Carl,

there is no problem with me and you are very kind to help me since several days.

Now I master the process on Excel and the calculus of the coef 'ai' is very simple, fast and reliable. I can verify the method with several check-points and the final results are similar than others results obtained with R, Statistica, XLSTAT,...

Have a nice day.  

@Carl Love Hello Carl,

Above, I have just given a copy of the 80 datas extracted from my excel sheet. Obviously, I define a matrix in Maple when I imported the datas with instruction : Mat2 := ExcelTools:-Import("filetest.xlsx", "Somme", "G2:G81") .

Concerning the precision of the result, I have calculated all the (ai) coefficients with the Shapiro-Wilks matrix formulas, in order to estimate W then the p-value. I verified also my result of W with the square of the correlation coefficient between the ai coef and the xi datas. It is OK. (the total calculous takes only a few seconds with EXCEL).

I confirm that the caculous from Maple doesn't seem to be right.

I am going to test your 2 ligns. I will inform you.

Thank you very much for help.

Hello Acer, 

here is the Mat2 sample of 80 datas :

60
71
77
81
83
84
86
88
93
95
96
98
105
106
107
109
110
112
114
114
115
117
119
120
122
123
124
124
125
126
128
129
131
131
131
132
132
135
135
136
136
137
137
137
139
140
140
141
141
142
143
143
144
145
145
146
147
148
149
149
150
151
151
151
154
155
156
156
158
158
160
162
163
164
172
182
183
183
184
197

 thank you for your interest in my question,

@dharr 

Thank you DHARR,

the twos solutions run very well.

@Carl Love 

Maple is a very subtle soft.

May you indicate me a user-guide book or a good pdf in order to improve the using of Maple? Thanks.  

@Carl Love

ouah, it is very kind of you to help me. It runs very well 

@Carl Love 

Hello Carl,

thanks for help.

I try Array but it doesn't run.

It is very difficult to use Maple.

For example, I have a matrix 1 colonne. I calculate the variable "moy" with function Mean (of the column). It is OK.

But if I want to generate a Normal distribution with instruction " X := RandomVariable(Normal(moy, 1))" it doesn't run.

There is an error because "moy" isn't a Real number but a matrix element...!!!!

I don't know how to convert a matrix element into a real...

A lot of problems to solve before running very simple process... ...

And if I 

@Carl Love 

thank you for help.

as you describe, there is not direct function to calculate p-value.

I have read that for bi-latteral test :

p-value = 2*P(ST >|St| | H0 true) = 2*(1-CDF(abs(St)).

I think you are right to make a difference between asymmetric and symmetric distribution.

I you have the answer, thanks to you.

@Carl Love 

Hello Carl,

thank you very much for further information.I have studied it tis week-end. I think it is OK.

But may you explain to me if it is possible with Maple, to calculate directly the P-Value?

Thanks for your help

@mmcdara Hi,

thank you very much every body for your very interesting answer. I am going to study it.

Kinds regards,

Wes

@Carl Love Hello Carl,

thank you very much for the answer.

I just don't unbderstand one thing.  

Y := ChiSquareRandomVariable(2);
 PDF(Y, 0.05);

doesn't run but this function runs very well with the Normal law :

X := RandomVariable(Normal(0, 1));
evalf(CDF(X, 0));

Which is really the différence?

Thanks very much for help and excuse-me for my very bad english (I am french!)

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