I think the answer is B.
Hope this helps.
A binomial probability density function should be used to represent the probability
<h3>How to determine the type of
probability density?</h3>
The given parameters are:
- Proportion that plays sport, p = 32%
- Number of students selected, p = 50
- The probability, P = (x ≤ 15)
The proportion that plays sport indicates that
68% of the students do not play sport
So, we have two events, which are
- Play sport
- Do not play sport
When there are two possible events, then the binomial probability density function should be used
Read more about binomial probability density at:
brainly.com/question/15246027
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The expected completion time is μ = 40 weeks.
The random variable, X = 38 weeks (the probable time)
If the standard deviation is σ, then the z-score is z = (x - μ)/σ.
Let us test the given standard deviations.
When σ=1,
z = (38-40)/1 = -2
From standard tables,
P(x<=38) = P(z<=-2) = 0.0228 =2.3%
When σ=2,
z = (38*40)/2 = -1
P(x<=38) = P(z<=-1) = 0.1587 = 15.9%
When σ=4,
z = (38-40)/4 = -0.5
P(x<=38) = P(z<=-0.5) = 0.3085 = 30.9%
Answers:
z=1 => 2.3%
z=2 => 16% (approx)
z=4 => 31% (approx)
Chad makes $10 per yard, and he makes 3 yards
3 x 10 = 30
Chad makes $5 per hour, and he works 8 hours
5 x 8 = 40
30 + 40 = 70
Chad makes $70 in all
hope this helps