Direction Software LLP Data Scientist interview questions

1 order and 2nd order differential. what is dy/dx actually means what is normal dist. why only use normal dist. and not other dist. instead what is cross entropy what t test why n-1 in sample variance formula and not only n in denominator what is p value , why it is set to only and only 0.05 and not any other value percentile and quartile what is time series what is moving avg what is acf and pacf explain arima , sarima , sarimax. give me example of time series what is ada fuller test and why we use it? what is cnn , how convolution operation happens in cnn , max pooling etc.