Based on the Normal Distribution, what statement is wrong.

If we believe that monthly returns are Normally distributed with a standard deviation of $5\%,$ a monthly return higher than $15\%$ or lower than $-15\%($a $3-$sigma event$)$ should happen approximately only once every $25$ years.

The index returns of the last eight years suggest that stock returns do not perfectly fit the Normal distribution. There have been too many outliers.

If we believe that monthly returns are Normally distributed with a standard deviation of $5\%,$ a monthly return higher than $10\%$ should happen approximately once every year, on average

If we believe that monthly returns are Normally distributed with a standard deviation of $5\%,$ a monthly return lower than $-5\%$ should happen approximately once every $6$ months, on average.