1.3/8 I THINK
2.12
3.True
4.67.118
5. 180
6. 22/ 5
7. 7/4
8.1/8
I hope It'll help you!
Answer:
B) approximately normal with mean 2.3 and standard deviation 2
Step-by-step explanation:
Given the following :
Mean crimes per day = 2.3
Standard deviation = 2
Number of samples = 100
Sampling distribution of the mean:
According to the central limit theorem:
Sample mean = population mean
2.3 = 2.3
The standard deviation of the sample (s) : ratio of the population standard deviation and square root of the sample size.
s = population standard deviation / √sample size
s = 2 / √100
s = 2 / 10
s = 0.2
The central limit theorem also posits that once ths sample size is large enough, the sampling of the sample mean will be approximately normal.
Hence, the distribution is approximately normal, with mean of 2.3 and standard deviation of 0.2
Answer:
Step-by-step explanation:I think the answer is D.
Answer:
There is a 99.99998% probability that at least one valve opens.
Step-by-step explanation:
For each valve there are only two possible outcomes. Either it opens on demand, or it does not. This means that we use the binomial probability distribution to solve this problem.
Binomial probability distribution
The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.
In which 
is the number of different combinatios of x objects from a set of n elements, given by the following formula.
And p is the probability of X happening.
In this problem we have that:
Calculate P(at least one valve opens).
This is 
Either no valves open, or at least one does. The sum of the probabilities of these events is decimal 1. So:
So
Finally
There is a 99.99998% probability that at least one valve opens.
