Answer:
(a) -3.708
(b) 1.706
(c) 0.490
Explanation:
The z-score of normal distribution is given as:
![z=(x-\mu)/(\sigma)](https://img.qammunity.org/2020/formulas/mathematics/high-school/hq285311c9d1m36eo8c9nqykppzmieuuwe.png)
(a)
Given:
Score is,
![x=268](https://img.qammunity.org/2020/formulas/mathematics/middle-school/n8lh2b1ht04eorvhiwvq5434z6rrmhiss9.png)
Mean value is,
![\mu =425](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6q6x2ahs14o1lzngbl7rn2sog1zzngftty.png)
Standard deviation is,
![\sigma = 51](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2oky4n59eychl6a9e0sp7iwwgwzaqm1rfm.png)
z-score is,
![z=(268-425)/(51)=(-157)/(51)=-3.078](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8xapzmc3ubbe012u1n82cqvkreucrsmqyc.png)
(b)
Given:
Score is,
![x=512](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5c4ib5eyop6b5j16k8zafpv6zsdlunp3al.png)
Mean value is,
![\mu =425](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6q6x2ahs14o1lzngbl7rn2sog1zzngftty.png)
Standard deviation is,
![\sigma = 51](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2oky4n59eychl6a9e0sp7iwwgwzaqm1rfm.png)
z-score is,
![z=(512-425)/(51)=(87)/(51)=1.706](https://img.qammunity.org/2020/formulas/mathematics/middle-school/czb8yu1cet0xamjwu2kinir46zhlvxb794.png)
(c)
Given:
Score is,
![x=450](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xc7ilpzz0vbplj55wax227rfdsmkfcfm49.png)
Mean value is,
![\mu =425](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6q6x2ahs14o1lzngbl7rn2sog1zzngftty.png)
Standard deviation is,
![\sigma = 51](https://img.qammunity.org/2020/formulas/mathematics/middle-school/2oky4n59eychl6a9e0sp7iwwgwzaqm1rfm.png)
z-score is,
![z=(450-425)/(51)=(25)/(51)=0.490](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fyas23sx7x1wbxsaqacgp6c1t21ii4gyoz.png)