Answer:
a) 0.0003
b) 0.035
Explanation:
We are given the following information in the question:
Mean, μ = 9.87 hours
Standard Deviation, σ = 1.1 hours
We are given that the distribution of hours of sleep is a bell shaped distribution that is a normal distribution.
Formula:

a) P(student gets less than 6.1 hours of sleep)
P(x < 6.1)
Calculation the value from standard normal z table, we have,

c)P(student gets between 6.5 and 7.89 hours of sleep)
