The answer is 31 1/6, I hope this helps!
Answer:
2
Step-by-step explanation:
First you add 4 to both sides and get
2x=4
then you divide by 2 and get
4/2=x
4/2=2
x=2
I hope this helps you
Formula => I=PRT
900=7500.R.2
R=900/15000
R=0,06
1) Call x the sample mean = 3.56
2) Call s the sample standard deviation = 0.2
3) Given that the variable is normally distributed and the sample is large, you determine the interval of confidence from:
x +/- Z(0.5) s/√n
Wehre Z(0.5) is the value of the probabilities over 5% (90% of confidence mean to subtract 10%, which is 5% for each side (tails) of the normal distribuition) and is taken from tables.
Z(0.5) = 0.3085
Then the inteval is
x +/- 0.385 *s /√n = 3.56 +/- 0.385 * 0.2/√45
3.56 +/- 0.011 = ( 3.549, 3.571). This is the answer.
Answer: The running time should at least 119.32 seconds to be in the top 5% of runners.
Step-by-step explanation:
Let X= random variable that represents the running time of men between 18 and 30 years of age.
As per given, X is normally distrusted with mean 
and standard deviation 
.
To find: x in top 5% i.e. we need to find x such that P(X<x)=95% or 0.95.
i.e. 
Since, z-value for 0.95 p-value ( one-tailed) =1.645
So,
Hence, the running time should at least 119.32 seconds to be in the top 5% of runners.
