(a) Average time to get to school
Average time (minutes) = Summation of the two means = mean time to walk to bus stop + mean time for the bust to get to school = 8+20 = 28 minutes
(b) Standard deviation of the whole trip to school
Standard deviation for the whole trip = Sqrt (Summation of variances)
Variance = Standard deviation ^2
Therefore,
Standard deviation for the whole trip = Sqrt (2^2+4^2) = Sqrt (20) = 4.47 minutes
(c) Probability that it will take more than 30 minutes to get to school
P(x>30) = 1-P(x=30)
Z(x=30) = (mean-30)/SD = (28-30)/4.47 ≈ -0.45
Now, P(x=30) = P(Z=-0.45) = 0.3264
Therefore,
P(X>30) = 1-P(X=30) = 1-0.3264 = 0.6736 = 67.36%
With actual average time to walk to the bus stop being 10 minutes;
(d) Average time to get to school
Actual average time to get to school = 10+20 = 30 minutes
(e) Standard deviation to get to school
Actual standard deviation = Previous standard deviation = 4.47 minutes. This is due to the fact that there are no changes with individual standard deviations.
(f) Probability that it will take more than 30 minutes to get to school
Z(x=30) = (mean - 30)/Sd = (30-30)/4.47 = 0/4.47 = 0
From Z table, P(x=30) = 0.5
And therefore, P(x>30) = 1- P(X=30) = 1- P(Z=0.0) = 1-0.5 = 0.5 = 50%
Answer:
58 feet.
Step-by-step explanation
Since the angle given is across from the length we need to find and we are given the hypotenuse, we use sine.
Sin(46)=x/80 where x is the height of the triangle and 80 is the hypotenuse.
80sin(46)=x
x=57.55 or 58 feet.
Answer:
Your answer is 
Step-by-step explanation:
That is kind of hard. I have used the internet to help create that repeating decimal to a fraction and got that as your answer.
3.10/155= 0.02 } subtract = 0.07 more
7.65/85= 0.09 }
Answer: 86.64%
Step-by-step explanation:
Let x be a random variable that represents the diameter of metal samples.
Given : Population mean : 
Standard deviation: 
Specified tolerance on the diameter is 0.75 mm.
i.e. range of diameter = 10-0.75< x <10+0.75 = 9.25< x< 10.75
Formula to find the z-score corresponds to x: 
At x= 0.75, 
Using standard normal table for z-value,
P-value : 
∴ Percentage of samples manufactured using this process satisfy the tolerance specification = 86.64%
