Voici le post de départ (enlevé parce qu’il contient la réponse à la question)
Hi Guillaume
Of course, i will gladly share my code and numbers 
Ok, so here is what I got. After loading the data like suggested at the beginning of Q8:
import pandas as pd
adult_census = pd.read_csv("../datasets/adult-census.csv")
target = adult_census["class"]
data = adult_census.select_dtypes(["integer", "floating"])
data = data.drop(columns=["education-num"])
Then loading:
from sklearn.linear_model import LogisticRegression
from sklearn.preprocessing import StandardScaler
from sklearn.pipeline import make_pipeline
from sklearn.model_selection import cross_validate
from sklearn.dummy import DummyClassifier
And doing:
model = make_pipeline(StandardScaler(), LogisticRegression())
res = cross_validate(model, data, target, cv=10, return_estimator=True)
print(res['test_score'].mean())
Givies me this result:
0.7998445658834604
Looking at the code in the explanation, it is exactly the same, with some different naming conventions giving the same result when I execute it.
Now doing the same with dummy:
model_d = make_pipeline(StandardScaler(), DummyClassifier())
res_d = cross_validate(model_d, data, target, cv=10, return_estimator=True)
print(res_d['test_score'].mean(), res_d['test_score'].mean()+0.04)
Gives me the output:
0.7607182352166999 0.8007182352166999
Double-checking with the code you provide in the explanation (thinking that maybe using the strategy=“most_frequent” would change the result), I still get the same result, i.e.
0.7607182352166999.
If these numbers are indeed correct then the logistic regression is not better by an amount of 0.04 or more. I know it is petty, but being a mathematician I take boundaries seriously 
As the number is indeed very close to an increase of 0.04 I think a tilde in the answer would solve the insecurity if other people have the same thoughts as I was having. I.e.
Better/Worse than a dummy classifier with an increase/decrease of ~0.04
This would have led me to ckeck answer c) as the tilde suggests that the boundary of 0.04 does not have to be taken 100% seriously.
Thanks again for the great course and also for taking the time to answer to all of these questions (not only mine I mean). You guys and gals are awesome 
Best
Manu