Answer:
0.9007 is the probability that a student scored below 86 on this exam.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 77
Standard Deviation, σ = 7
We are given that the distribution of examination grades is a bell shaped distribution that is a normal distribution.
Formula:
[tex]z_{score} = \displaystyle\frac{x-\mu}{\sigma}[/tex]
a) P(student scored below 86)
P(x < 86)
[tex]P( x < 86) = P( z < \displaystyle\frac{86 - 77}{7}) = P(z < 1.2857)[/tex]
Calculation the value from standard normal z table, we have,
[tex]P(x < 1.2857) = 0.9007 = 90.07\%[/tex]
0.9007 is the probability that a student scored below 86 on this exam.
