A tank contains 3,000 L of brine with 15 kg of dissolved salt. Pure water enters the tank at a rate of 30 L/min. The solution is
1 answer:
You might be interested in
Answer:
The 90% confidence interval for the average bonus that all employees working for financial companies in New York City received last year is between $43,819 and $50,181
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.
T interval
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 62 - 1 = 61
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 61 degrees of freedom(y-axis) and a confidence level of . So we have T = 1.67
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 47000 - 3181 = $43,819
The upper end of the interval is the sample mean added to M. So it is 47000 + 3181 = $50,181
The 90% confidence interval for the average bonus that all employees working for financial companies in New York City received last year is between $43,819 and $50,181
Answer:
Probability that a battery will last more than 19 hours is 0.0668.
Step-by-step explanation:
We are given that the lifetime of a battery in a certain application is normally distributed with mean μ = 16 hours and standard deviation σ = 2 hours.
<em>Let X = lifetime of a battery in a certain application</em>
So, X ~ N()
The z-score probability distribution for normal distribution is given by;
Z = ~ N(0,1)
where, = mean lifetime = 16 hours
= standard deviation = 2 hours
The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X.
So, the probability that a battery will last more than 19 hours is given by = P(X > 19 hours)
P(X > 19) = P( >
) = P(Z > 1.50) = 1 - P(Z
1.50)
= 1 - 0.9332 = 0.0668
<em>Now, in the z table the P(Z </em><em> x) or P(Z < x) is given. So, the above probability is calculated by looking at the value of x = 1.50 in the z table which has an area of 0.9332.</em>
Hence, the probability that a battery will last more than 19 hours is 0.0668.
