Given X∼N(0,1)X \sim N(0, 1)X∼N(0,1), what is P(−1≤Z≤1)P(-1 \le Z \le 1)P(−1≤Z≤1)? (Approximately)
68%68\%68%
95%95\%95%
99.7%99.7\%99.7%
50%50\%50%