Answer:
3 students
Step-by-step explanation:
Two ways you can do this:
1. If you have a graphic calculator you can find the normal distribution function and enter the following values to get the probability of a student finished in less than 5 minutes:
Lower: 0
Upper: 5
Standard Deviation: 1
Mean: 6
This gives a probability of: 0.1587 (4.d.p)
2. You can use the formula and find the probability using the Z-table.
[tex]Z = \frac{x - \mu}{\sigma}[/tex]
Substitute known values:
[tex]Z = \frac{5 - 6}{1}\\Z = -1/1 = -1\\[/tex]
It is one standard deviation to the left of the mean,.
Look up on Z-score table and we get: 0.1587 (4.d.p)
Now we need to find expected number. We do this by multiplying the probability by the amount of people:
0.1587 x x19 = 3.0153 rounded to 3 students.
Hope this helped!
