Which one of the following statements is NOT correct?

1. When the water content of soil lies between its liquid limit and plastic limit, the soil is said to be in plastic state.
2. Boussinesq's theory is used for the analysis of stratified soil.
3. The inclination of stable slope in cohesive soil can be greater than its angle of internal friction
4. For saturated dense fine sand, after applying overburden correction, if  the Standard Penetration Test value exceeds $15$, dilatancy correction is to be applied