You want to purchase a house for $185,000. To avoid certain costs, you want to make a down payment of 20%. What is
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Answer:
The probability that exactly one of these mortgages is delinquent is 0.357.
Step-by-step explanation:
We are given that according to the Mortgage Bankers Association, 8% of U.S. mortgages were delinquent in 2011. A delinquent mortgage is one that has missed at least one payment but has not yet gone to foreclosure.
A random sample of eight mortgages was selected.
The above situation can be represented through Binomial distribution;
where, n = number of trials (samples) taken = 8 mortgages
r = number of success = exactly one
p = probability of success which in our question is % of U.S.
mortgages those were delinquent in 2011, i.e; 8%
<em>LET X = Number of U.S. mortgages those were delinquent in 2011</em>
So, it means X ~
Now, Probability that exactly one of these mortgages is delinquent is given by = P(X = 1)
P(X = 1) =
=
= 0.357
<u><em>Hence, the probability that exactly one of these mortgages is delinquent is 0.357.</em></u>
Answer:
The 90% confidence interval for the mean test score is between 77.29 and 85.71.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution to solve this question.
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 = 25 - 1 = 24
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a confidence level of . So we have T = 2.064
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 81.5 - 4.21 = 77.29
The upper end of the interval is the sample mean added to M. So it is 81.5 + 4.21 = 85.71.
The 90% confidence interval for the mean test score is between 77.29 and 85.71.