Answer:
The 90% confidence interval for the mean combined fuel economy for Ford Explorers is between 22.95 and 23.63 mpg.
Step-by-step explanation:
We have the standard deviation for the sample, which means that the t-distribution is used 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 = 16 - 1 = 15
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 15 degrees of freedom(y-axis) and a confidence level of 
. So we have T = 1.7531
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 23.29 - 0.34 = 22.95 mpg
The upper end of the interval is the sample mean added to M. So it is 23.29 + 0.34 = 23.63 mpg
The 90% confidence interval for the mean combined fuel economy for Ford Explorers is between 22.95 and 23.63 mpg.
9514 1404 393
Answer:
Step-by-step explanation:
The slope of a line is the tangent of the angle it makes with the x-axis. The given line has a slope of -1/3, so the lines we want will have slopes of ...
m1 = tan(arctan(-1/3) +45°) = 0.5 . . . . . using a calculator
m2 = tan(arctan(-1/3) -45°) = -2
Of course, these two lines are perpendicular to each other, so their slopes will have a product of -1: (0.5)(-2) = -1.
__
We can use the point-slope form of the equation for a line to write the desired equations:
y = m(x -h) +k . . . . . line with slope m through point (h, k)
<u>Line 1</u>:
y = 1/2(x -2) +3
y = 1/2x +2
<u>Line 2</u>:
y = -2(x -2) +3
y = -2x +7
Answer:
n=42
Step-by-step explanation:
Answer:
0.0082 = 0.82% probability that he will pass
Step-by-step explanation:
For each question, there are only two possible outcomes. Either the students guesses the correct answer, or he guesses the wrong answer. The probability of guessing the correct answer for a question is independent of other questions. So we use the binomial probability distribution to solve this question.
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 combinations 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:
.
If the student makes knowledgeable guesses, what is the probability that he will pass?
He needs to guess at least 9 answers correctly. So
0.0082 = 0.82% probability that he will pass
Answer:
47.4%
Step-by-step explanation:
The total amount Louise spent on Frappuccinos was 4×$4.50 = $18. The fraction that is of the total is ...
Fraps/Total = $18/$38 = 9/19
That can be converted to a percentage by multiplying by 100%:
9/19 = (9/19)×100% ≈ 47.4%
Louise spent 47.4% of the $38 on Frappuccinos.
_____
<em>Additional comment</em>
The decimal equivalent of 9/19 is a repeating decimal with an 18-digit repeat.
