mr. larsen's third grade class has 22 students, 12 girls and 10 boys. two students must be selected at random to be in the fall
1 answer:
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Answer:
a) 81.5%
b) 95%
c) 75%
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 266 days
Standard Deviation, σ = 15 days
We are given that the distribution of length of human pregnancies is a bell shaped distribution that is a normal distribution.
Formula:
a) P(between 236 and 281 days)
b) a) P(last between 236 and 296)
c) If the data is not normally distributed.
Then, according to Chebyshev's theorem, at least data lies within k standard deviation of mean.
For k = 2
Atleast 75% of data lies within two standard deviation for a non normal data.
Thus, atleast 75% of pregnancies last between 236 and 296 days approximately.
Answer:
P(X 74) = 0.3707
Step-by-step explanation:
We are given that the score of golfers for a particular course follows a normal distribution that has a mean of 73 and a standard deviation of 3.
Let X = Score of golfers
So, X ~ N()
The z score probability distribution is given by;
Z = ~ N(0,1)
where, = population mean = 73
= standard deviation = 3
So, the probability that the score of golfer is at least 74 is given by = P(X 74)
P(X 74) = P(
) = P(Z
0.33) = 1 - P(Z < 0.33)
= 1 - 0.62930 = 0.3707
Therefore, the probability that the score of golfer is at least 74 is 0.3707 .