A geneticist crossed two mice with yellow hair. The yellow hair allele ($Y$) is dominant to the grey hair allele ($y$), but is embryonic lethal when homozygous ($YY$).

The surviving offspring observed were:

• 238 mice with yellow hair
• 116 mice with grey hair

Calculate the simplified ratio of offspring with yellow hair to offspring with grey hair.

Give your answer in the form $X:1$, where $X$ is rounded to the nearest whole number.