If Z~N(0,1), find upper quartile and the lower quartile. Find also the 70th percentile?

4.
For z-table, refer to: https://www.ztable.net/

For the upper quartile:
P(z > a) = 1/4
P(z < -a) = 0.25
According to the z-table:
-a = -0.67 - 0.01 × (0.25143 - 0.25)/(0.25143 - 0.24825) = -0.674
Hence, the upper quartile, a = 0.674

For the lower quartile:
P(z < a) = 1/4
P(z < a) = 0.25
According to the z-table:
a = -0.67 - 0.01 × (0.25143 - 0.25)/(0.25143 - 0.24825) = -0.674
Hence, the upper quartile, a = -0.674

For the 70th percentile:
P(z < a) = 70%
1 - P(z > a) = 0.7
P(z > a) = 0.3
P(z < -a) = 0.3
According to the z-table:
-a = -0.52 - 0.01 × (0.30153 - 0.3)/(0.30153 - 0.29806) = -0.524
Hence, the 70th percentage, a = 0.524