Answer:
option B
Step-by-step explanation:
Given,
mean result (μ) = 65
standard deviation (σ)= 15
probability that student will score between 50 and 80
= [tex]P(50< x <80 )= P[\dfrac{50-65}{15} < \dfrac{x-\mu}{\sigma} / \sigma < \dfrac{80-65}{15}][/tex]
= [tex]P(50< x <80 )= P[\dfrac{-15}{15} < z / \sigma < \dfrac{15}{15}][/tex]
= [tex]P(50< x <80 )= P[-1< z / \sigma <1][/tex]
= P(Z < 1) - P(Z < -1)
Using z table,
= 0.8413 - 0.1587
= 0.6826
the correct answer is option B
