Answer: p = 1/25
Step-by-step explanation:
Ok, you know that the probability of rolling a six is p = 1/5
now, if you want to have two sixes, then you have two events with a probability of 1/5.
And as you know the joint probability for two events is equal to the product of the probabilities, then the probability of rolling two sixes is:
p = (1/5)*(1/5) = 1/25.
The life of an electric component has an exponential distribution with a mean of 8.9 years. What is the probability that a randomly selected one such component has a life more than 8 years? Answer: (Round to 4 decimal places.)
Answer:
[tex] P(X>8)[/tex]
And for this case we can use the cumulative distribution function given by:
[tex] F(x) = 1- e^{-\lambda x}[/tex]
And if we use this formula we got:
[tex] P(X>8)= 1- P(X \leq 8) = 1-F(8) = 1- (1- e^{-\frac{1}{8.9} *8})=e^{-\frac{1}{8.9} *8}= 0.4070[/tex]
Step-by-step explanation:
For this case we can define the random variable of interest as: "The life of an electric component " and we know the distribution for X given by:
[tex]X \sim exp (\lambda =\frac{1}{8.9}) [/tex]
And we want to find the following probability:
[tex] P(X>8)[/tex]
And for this case we can use the cumulative distribution function given by:
[tex] F(x) = 1- e^{-\lambda x}[/tex]
And if we use this formula we got:
[tex] P(X>8)= 1- P(X \leq 8) = 1-F(8) = 1- (1- e^{-\frac{1}{8.9} *8})=e^{-\frac{1}{8.9} *8}= 0.4070[/tex]
please - i got this wrong so plz help
Answer:
Area = 108 cm^2
Perimeter = 44 cm
Step-by-step explanation:
Area, -->
24 + 30 + 24 + 30 -->
24(2) + 30(2)
48 + 60 = 108 cm^2
108 = area
10 + 12 + 10 + 12, -->
10(2) + 12(2) = 44 cm
44 = perim.
Hope this helps!
Answer:
Step-by-step explanation:
Draw the diagram.
This time put in the only one line for the height. That is only 1 height is 8 cm. That's it.
The base is 6 + 6 = 12 cm.
The slanted line is 10 cm
That's all your diagram should show. It is much clearer without all the clutter.
Now you are ready to do the calculations.
Area
The Area = the base * height.
base = 12
height = 8
Area = 12 * 8 = 96
Perimeter.
In a parallelagram the opposite sides are equal to one another.
One set of sides = 10 + 10 = 20
The other set = 12 + 12 = 24
Both sets = 20 + 24
Both sets = 44
Answer
Area = 96
Perimeter = 44
3 squared times 3 squared simplified
Answer:
3^4
Step-by-step explanation:
3^2*3^2
3*3*3*3
3^4
A manager bought 12 pounds of peanuts for $30. He wants to mix $5 per pound cashews with the peanuts to get a batch of mixed nuts that is worth $4 per pound. How many pounds of cashews are needed
Answer:
18 pounds of cashews are needed.
Step-by-step explanation:
Given;
A manager bought 12 pounds of peanuts for $30.
Price of peanut per pound P = $30/12 = $2.5
Price of cashew per pound C = $5
Price of mixed nut per pound M = $4
Let x represent the proportion of peanut in the mixed nut.
The proportion of cashew will then be y = (1-x), so;
xP + (1-x)C = M
Substituting the values;
x(2.5) + (1-x)5 = 4
2.5x + 5 -5x = 4
2.5x - 5x = 4 -5
-2.5x = -1
x = 1/2.5 = 0.4
Proportion of cashew is;
y = 1-x = 1-0.4 = 0.6
For 12 pounds of peanut the corresponding pounds of cashew needed is;
A = 12/x × y
A = 12/0.4 × 0.6 = 18 pounds
18 pounds of cashews are needed.
A professional employee in a large corporation receives an average of μ = 39.8 e-mails per day. Most of these e-mails are from other employees in the company. Because of the large number of e-mails, employees find themselves distracted and are unable to concentrate when they return to their tasks. In an effort to reduce distraction caused by such interruptions, one company established a priority list that all employees were to use before sending an e-mail. One month after the new priority list was put into place, a random sample of 38 employees showed that they were receiving an average of x = 33.1 e-mails per day. The computer server through which the e-mails are routed showed that σ = 16.2. Has the new policy had any effect? Use a 10% level of significance to test the claim that there has been a change (either way) in the average number of e-mails received per day per employee.
Answer:
Step-by-step explanation:
Null hypothesis: u = 39.8
Alternative: u =/ 39.8
Using a one sample z test: the formula is
z = x-u / (sd/√n)
Where x = 33.1 u = 39.8, sd= 16.2 and n = 38
Thus we have:
z = 33.1-39.8 / (16.2/√38)
z = -6.7 / (16.2/6.1644)
z = -6.7/ 2.6280
z= -2.5495
To be able to arrive at a conclusion, we have to find the p value, the p value at a 0.1 significance level for a two tailed test is 0.0108. This is way less than 0.1 thus we will reject the null and conclude that there has been a change (either way) in the average number of e-mails received per day per employee. Yes, the new policy had an effect.
Please show you work for both 5 and 6!
Answer:
5-c) 6-c)
Step-by-step explanation:
5 c)= (a^4)^(1/3)= a^(4*1/3)=a^(4/3)
6. At the beginning of 1st year the total value on the bank account=500 USD
At the end of 1-st year the total value is 500 USD +3% from 500 USD=
500+500*0.03= 500*1.03
At the end of 2-nd year the total amount is 500*1.03+3% from 500*1.03=
500*1.03^2
Similarly at the end of the 3-rd year the total amount is 500*1.03^3
Finally at the end of fourth year the total amount is 500*1.03^4
I need help on khan academy and I’m willing to pay half right when you start the work and when you finish all the work I’ll pay the other half. I am desperate if I don’t pass this class it’s bad for me. Comment your number,snap anything. If not can you please help me with this one problem please thank youu
Answer:
[tex]x\approx 50^\circ[/tex]
Step-by-step explanation:
[tex]c^2 = a^2 + b^2 - 2ab(cos(C))[/tex]
See the figure below to get the values as:
[tex]7^2=7^2+9^2-2\left(7\right)\left(9\right)cos\left(x\right)\\\\cos(x)=\frac{7^2+9^2-7^2}{2\cdot \:7\cdot \:9}\\\\x\approx 50^\circ[/tex]
There are multiple concepts to solve this problem. This is one of the concept used in high school. Other concept to solve this problem is to use the concept of isosceles triangle. An isosceles triangle is a triangle with (at least) two equal sides. The angles shared by the two equal sides are also equal. So that the sum of all the three angles will add up to 180.
[tex]x+x+80=180\\\\2x=100\\\\x=50^{\circ}[/tex]
Best Regards!
Solve for x. 9x-2c=k
Ken runs 12 miles in a marathon. Every 3.5 miles, he stopes to take a drink. How many times does he stop during the marathon ?
Answer:
Brainleist!
Step-by-step explanation:
12/3.5
3.42857142857
round down so its 3!
Solve: x + 7 < 3 plsss help me
Answer:
The answer is -4.
Step-by-step explanation:
You should get this answer if you do 3 - 7.
What is the simplified form of the expression 3cubed root b^2
Answer:
Step-by-step explanation:
[tex](\sqrt{b^{2}})^{3}=b^{3}\\\\[/tex]
or If it is
[tex]\sqrt[3]{b^{2}} =(b^{2})^{\frac{1}{3}}=b^{2*\frac{1}{3}}=b^{\frac{2}{3}}[/tex]
What is the area of this triangle?
Answer:
Option (D)
Step-by-step explanation:
Formula for the area of a triangle is,
Area of a triangle = [tex]\frac{1}{2}(\text{Base})(\text{Height})[/tex]
For the given triangle ABC,
Area of ΔABC = [tex]\frac{1}{2}(\text{AB})(\text{CD})[/tex]
Length of AB = [tex](y_2-y_1)[/tex]
Length of CD = [tex](x_3-x_1)[/tex]
Now area of the triangle ABC = [tex]\frac{1}{2}(y_2-y_1)(x_3-x_1)[/tex]
Therefore, Option (D) will be the answer.
If a coin is tossed 4 times, and then a standard six-sided die is rolled 3 times, and finally a group of two cards are drawn from a standard deck of 52 cards without replacement, how many different outcomes are possible?
Answer: 4,582,656
Step-by-step explanation:
A coin is tossed 4 times,
2^4 outcomes: 16
and then a standard six-sided die is rolled 3 times, 6^3
216 outcomes:
and finally, a group of two cards is drawn from a standard deck of 52 cards without replacements
It says a “group”, so, I guess the order doesn’t matter… So it is “52 choose 2”
52*51/ (2*1) = 26*51
how many different outcomes are possible?
16*216*26*51 = 4,582,656
15. Simplify sin(90° - O) cos 0 - sin(180° +0) sin e.
Answer: cos²(θ) + sin(θ)sin(e)
Step-by-step explanation:
sin (90° - θ)cos(Ф) - sin(180° + θ) sin(e)
Note the following identities:
sin (90° - θ) = cos(x)
sin (180° + θ) = -sin(x)
Substitute those identities into the expression:
cos(x)cos(x) - -sin(x)sin(e)
= cos²(x) + sin(x)sin(e)
The cost of unleaded gasoline in the Bay Area once followed a normal distribution with a mean of $4.74 and a standard deviation of $0.16. Sixteen gas stations from the Bay area are randomly chosen. We are interested in the average cost of gasoline for the 15 gas stations. What is the approximate probability that the average price for 15 gas stations is over $4.99?
Answer:
Approximately 0% probability that the average price for 15 gas stations is over $4.99.
Step-by-step explanation:
To solve this question, we need to understand the normal probability distribution and the central limit theorem.
Normal probability distribution
When the distribution is normal, we use the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value 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. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
Central Limit Theorem
The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].
For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.
In this question, we have that:
[tex]\mu = 4.74, \sigma = 0.16, n = 16, s = \frac{0.16}{\sqrt{16}} = 0.04[/tex]
What is the approximate probability that the average price for 15 gas stations is over $4.99?
This is 1 subtracted by the pvalue of Z when X = 4.99. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
By the Central Limit Theorem
[tex]Z = \frac{X - \mu}{s}[/tex]
[tex]Z = \frac{4.99 - 4.74}{0.04}[/tex]
[tex]Z = 6.25[/tex]
[tex]Z = 6.25[/tex] has a pvalue very close to 1.
1 - 1 = 0
Approximately 0% probability that the average price for 15 gas stations is over $4.99.
Can someone please help me with this problem?
Answer: -13
Step-by-step explanation:
c-2y
= -5-2(4)
= -5 - 8
= -13
Answer:
-13
Step-by-step explanation:
[tex]c=-5\\y=4\\c-2y=\\-5-(4*2)=\\-5-8=\\-13[/tex]
The expression is equal to -13 when [tex]c=-5[/tex] and [tex]y=4[/tex].
. A bag contains 6 red and 3 black chips. One chip is selected, its color is recorded, and it is returned to the bag. This process is repeated until 5 chips have been selected. What is the probability that one red chip was selected?
Answer:
The probability that one red chip was selected is 0.0053.
Step-by-step explanation:
Let the random variable X be defined as the number of red chips selected.
It is provided that the selections of the n = 5 chips are done with replacement.
This implies that the probability of selecting a red chip remains same for each trial, i.e. p = 6/9 = 2/3.
The color of the chip selected at nth draw is independent of the other selections.
The random variable X thus follows a binomial distribution with parameters n = 5 and p = 2/3.
The probability mass function of X is:
[tex]P(X=x)={5\choose x}\ (\frac{2}{3})^{x}\ (1-\frac{2}{3})^{5-x};\ x=0,1,2...[/tex]
Compute the probability that one red chip was selected as follows:
[tex]P(X=1)={5\choose 1}\ (\frac{2}{3})^{1}\ (1-\frac{2}{3})^{5-1}[/tex]
[tex]=5\times\frac{2}{3}\times \frac{1}{625}\\\\=\farc{2}{375}\\\\=0.00533\\\\\approx 0.0053[/tex]
Thus, the probability that one red chip was selected is 0.0053.
Answer:
0.0412
Step-by-step explanation:
Total chips = 6 red + 3 black chips
Total chips=9
n=5
Probability of (Red chips ) can be determined by
=[tex]\frac{6}{9}[/tex]
=[tex]\frac{2}{3}[/tex]
=0.667
Now we used the binomial theorem
[tex]P(x) = C(n,x)*px*(1-p)(n-x).....Eq(1)\\ putting \ the \ given\ value \ in\ Eq(1)\ we \ get \\p(x=1) = C(5,1) * 0.667^1 * (1-0.667)^4[/tex]
This can give 0.0412
Find the equation for the line containing the points (-2,-5) and (6,3)
Answer:
y = x - 3
Step-by-step explanation:
Do rise/run to find the slope
8/8 = 1
y = x + b
Plug in a point to find the y-intercept
-5 = -2 + b
-3 = b
The equation will be y = x - 3
triangle STU is similar to triangle VWX. Which statement is true about the two triangles?
Answer:
Option 1.
Step-by-step explanation:
When triangles are similar, their angles cannot be proportional. The angles on both triangles have to be same.
Option 3 and 4 are wrong.
Angle T and angle U cannot be congruent on the same triangle.
Therefore, option 1 is correct.
The answer would be the third one because if they are simillar that means they are not exactly the same but one is a dillation of one. This means they are proportinate. Mark Branliest!!!!
According to a report an average person watched 4.55 hours of television per day in 2005. A random sample of 20 people gave the following number of hours of television watched per day for last year. At the 10% significance level, do the data provide sufficient evidence to conclude that the amount of television watched per day last year by the average person differed from that in 2005? 1.0 4.6 5.4 3.7 5.2 1.7 6.1 1.9 7.6 9.1 6.9 5.5 9.0 3.9 2.5 2.4 4.7 4.1 3.7 6.2 a. identify the claim and state and b. find the critical value(s) and identify the rejection region(s), c. find the standardized test statistic Sketch a graph decide whether to reject or fail to reject the null hypothesis, and d. interpret the decision in the context of the original claim. e. Obtain a 95%confidence interval
Answer:
a. The claim is that the amount of television watched per day last year by the average person differed from that in 2005.
b. The critical values are tc=-1.729 and tc=1.729.
The acceptance region is defined by -1.792<t<1.729. See the picture attached.
c. Test statistic t=0.18.
The null hypothesis failed to be rejected.
d. At a significance level of 10%, there is not enough evidence to support the claim that the amount of television watched per day last year by the average person differed from that in 2005.
e. The 95% confidence interval for the mean is (2.29, 7.23).
Step-by-step explanation:
We have a sample of size n=20, which has mean of 4.76 and standard deviation of 5.28.
[tex]M=\dfrac{1}{n}\sum_{i=1}^n\,x_i\\\\\\M=\dfrac{1}{20}(1+4.6+5.4+. . .+6.2)\\\\\\M=\dfrac{95.2}{20}\\\\\\M=4.76\\\\\\s=\dfrac{1}{n-1}\sum_{i=1}^n\,(x_i-M)^2\\\\\\s=\dfrac{1}{19}((1-4.76)^2+(4.6-4.76)^2+(5.4-4.76)^2+. . . +(6.2-4.76)^2)\\\\\\s=\dfrac{100.29}{19}\\\\\\s=5.28\\\\\\[/tex]
a. This is a hypothesis test for the population mean.
The claim is that the amount of television watched per day last year by the average person differed from that in 2005.
Then, the null and alternative hypothesis are:
[tex]H_0: \mu=4.55\\\\H_a:\mu\neq 4.55[/tex]
The significance level is 0.1.
The sample has a size n=20.
The sample mean is M=4.76.
As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=5.28.
The estimated standard error of the mean is computed using the formula:
[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{5.28}{\sqrt{20}}=1.181[/tex]
Then, we can calculate the t-statistic as:
[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{4.76-4.55}{1.181}=\dfrac{0.21}{1.181}=0.18[/tex]
The degrees of freedom for this sample size are:
[tex]df=n-1=20-1=19[/tex]
The critical value for a level of significance is α=0.10, a two tailed test and 19 degrees of freedom is tc=1.729.
The decision rule is that if the test statistic is above tc=1.729 or below tc=-1.729, the null hypothesis is rejected.
As the test statistic t=0.18 is within the critical values and lies in the acceptance region, the null hypothesis failed to be rejected.
There is not enough evidence to support the claim that the amount of television watched per day last year by the average person differed from that in 2005.
We have to calculate a 95% confidence interval for the mean.
The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.
The sample mean is M=4.76.
The sample size is N=20.
The standard error is s_M=1.181
The degrees of freedom for this sample size are df=19.
The t-value for a 95% confidence interval and 19 degrees of freedom is t=2.093.
The margin of error (MOE) can be calculated as:
[tex]MOE=t\cdot s_M=2.093 \cdot 1.181=2.47[/tex]
Then, the lower and upper bounds of the confidence interval are:
[tex]LL=M-t \cdot s_M = 4.76-2.47=2.29\\\\UL=M+t \cdot s_M = 4.76+2.47=7.23[/tex]
The 95% confidence interval for the mean is (2.29, 7.23).
I. In the testing of a new production method, 18 employees were selected randomly and asked to try the new method. The sample mean production rate for the 18 employees was 80 parts per hour and the sample standard deviation was 10 parts per hour. Provide 90% confidence intervals for the populations mean production rate for the new method, assuming the population has a normal probability distribution.
Answer:
The 90% confidence interval for the mean production rate fro the new method is (75.9, 84.1).
Step-by-step explanation:
We have to calculate a 90% confidence interval for the mean.
The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.
The sample mean is M=80.
The sample size is N=18.
When σ is not known, s divided by the square root of N is used as an estimate of σM:
[tex]s_M=\dfrac{s}{\sqrt{N}}=\dfrac{10}{\sqrt{18}}=\dfrac{10}{4.24}=2.36[/tex]
The degrees of freedom for this sample size are:
[tex]df=n-1=18-1=17[/tex]
The t-value for a 90% confidence interval and 17 degrees of freedom is t=1.74.
The margin of error (MOE) can be calculated as:
[tex]MOE=t\cdot s_M=1.74 \cdot 2.36=4.1[/tex]
Then, the lower and upper bounds of the confidence interval are:
[tex]LL=M-t \cdot s_M = 80-4.1=75.9\\\\UL=M+t \cdot s_M = 80+4.1=84.1[/tex]
The 90% confidence interval for the mean production rate fro the new method is (75.9, 84.1).
"The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects where order of selection is not important is called the"
Options
Counting rule for permutationsCounting rule for multiple-step experimentsCounting rule for combinationsCounting rule for independent eventsAnswer:
(C)Counting rule for combinations
Step-by-step explanation:
When selecting n objects from a set of N objects, we can determine the number of experimental outcomes using permutation or combination.
When the order of selection is important, we use permutation.However, whenever the order of selection is not important, we use combination.Therefore, The counting rule that is used for counting the number of experimental outcomes when n objects are selected from a set of N objects where order of selection is not important is called the counting rule for combinations.
A selection or listing of objects in which the order of the objects is not important
A student's course grade is based on one midterm that counts as 20% of his final grade, one class project that counts as 20% of his final grade, a set of homework assignments that counts as 30% of his final grade, and a final exam that counts as 30% of his final grade. His midterm score is 64, his project score is 80, his homework score is 94, and his final exam score is 77. What is his overall final score? What letter grade did he earn (A, B, C, D, or F)? Assume that a mean of 90 or above is an A, a mean of at least 80 but less than 90 is a B, and so on.
Answer:
His overall final score is 80.1.
His letter grade is a B.
Step-by-step explanation:
To find his grade, we multiply each grade by it's weight.
Grades and weights:
His midterm score is 64. The midterm counts 20% = 0.2.
His project score is 80. The project score counts 20% = 0.2.
His homework score is 94. The homework score counts 30%.
His final exam score is 77. It counts 30%.
What is his overall final score?
64*0.2 + 80*0.2 + 94*0.3 + 77*0.3 = 80.1
His overall final score is 80.1.
What letter grade did he earn (A, B, C, D, or F)?
At least 80 but less than 90 is a B. He scored 80.1, so his letter grade is a B.
Find an equation for this line.
Answer:
y = -0.4x - 3
Step-by-step explanation:
Using the slope formula, y2-y1/x2-x1 we need to find two points. Luckily, we already have two points, (5, -5) and (-5, -1). Plugging in, we have -4/10, or -0.4. Since now we know m = -0.4, we need to find the y-intercept. We have it as -3. Now we get y = -0.4x - 3 as our equation.
The equation f(x) is given as x2_4=0. Considering the initial approximation at
x0=6 then the value of x1 is given as
Select one:
O A. 10/3
O B. 7/3
O C. 13/3
O D. 4/3
Answer:
The value of [tex]x_{1}[/tex] is given by [tex]\frac{10}{3}[/tex]. Hence, the answer is A.
Step-by-step explanation:
This exercise represents a case where the Newton-Raphson method is used, whose formula is used for differentiable function of the form [tex]f(x) = 0[/tex]. The expression is now described:
[tex]x_{n+1} = x_{n} - \frac{f(x_{n})}{f'(x_{n})}}[/tex]
Where:
[tex]x_{n}[/tex] - Current approximation.
[tex]x_{n+1}[/tex] - New approximation.
[tex]f(x_{n})[/tex] - Function evaluated in current approximation.
[tex]f'(x_{n})[/tex] - First derivative of the function evaluated in current approximation.
If [tex]f(x) = x^{2} - 4[/tex], then [tex]f'(x) = 2\cdot x[/tex]. Now, given that [tex]x_{0} = 6[/tex], the function and first derivative evaluated in [tex]x_{o}[/tex] are:
[tex]f(x_{o}) = 6^{2} - 4[/tex]
[tex]f(x_{o}) = 32[/tex]
[tex]f'(x_{o})= 2 \cdot 6[/tex]
[tex]f'(x_{o}) = 12[/tex]
[tex]x_{1} = x_{o} - \frac{f(x_{o})}{f'(x_{o})}[/tex]
[tex]x_{1} = 6 - \frac{32}{12}[/tex]
[tex]x_{1} = 6 - \frac{8}{3}[/tex]
[tex]x_{1} = \frac{18-8}{3}[/tex]
[tex]x_{1} = \frac{10}{3}[/tex]
The value of [tex]x_{1}[/tex] is given by [tex]\frac{10}{3}[/tex]. Hence, the answer is A.
The maximum height of a vehicle that can safely pass under a bridge is 12 feet 5 inches. A truck measures 162 inches in height. Which best explains whether or not the truck can pass safely under the bridge?
162 inches is 13.5 feet or 13 feet 6 inches, so it would not fit underneath the bridge
Answer:
The truck cannot pass safely under the bridge. The truck is 13 inches taller than the maximum height.
Show all work to identify the asymptotes and zero of the faction f(x) = 4x/x^2 - 16.
Answer:
asymptotes: x = -4, x = 4zeros: x = 0Step-by-step explanation:
The vertical asymptotes of the rational expression are the places where the denominator is zero:
x^2 -16 = 0
(x -4)(x +4) = 0 . . . . . true for x=4, x=-4
x = 4, x = -4 are the equations of the vertical asymptotes
__
The zeros of a rational expression are the places where the numerator is zero:
4x = 0
x = 0 . . . . . . divide by 4
The time required for an automotive center to complete an oil change service on an automobile approximately follows a normal distribution, with a mean of 17 minutes and a standard deviation of 4 minutes. (a) The automotive center guarantees customers that the service will take no longer than 20 minutes. If it does take longer, the customer will receive the service for half-price. What percent of customers receive the service for half-price? (b) If the automotive center does not want to give the discount to more than 2% of its customers, how long should it make the guaranteed time limit?
Answer:
a) 22.66% of customers receive the service for half-price.
b) The guaranteed time limit should be of 25.2 minutes.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value 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. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question, we have that:
[tex]\mu = 17, \sigma = 4[/tex]
(a) The automotive center guarantees customers that the service will take no longer than 20 minutes. If it does take longer, the customer will receive the service for half-price. What percent of customers receive the service for half-price?
Longer than 20 minutes is 1 subtracted by the pvalue of Z when X = 20. So
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]Z = \frac{20 - 17}{4}[/tex]
[tex]Z = 0.75[/tex]
[tex]Z = 0.75[/tex] has a pvalue of 0.7734
1 - 0.7734 = 0.2266
22.66% of customers receive the service for half-price.
(b) If the automotive center does not want to give the discount to more than 2% of its customers, how long should it make the guaranteed time limit?
The time limit should be the 100 - 2 = 98th percentile, which is X when Z has a pvalue of 0.98. So X when Z = 2.054.
[tex]Z = \frac{X - \mu}{\sigma}[/tex]
[tex]2.054 = \frac{X - 17}{4}[/tex]
[tex]X - 17 = 4*2.054[/tex]
[tex]X = 25.2[/tex]
The guaranteed time limit should be of 25.2 minutes.
A randomly selected sample of college basketball players has the following heights in inches. See Attached Excel for Data. Compute a 95% confidence interval for the population mean height of college basketball players based on this sample and fill in the blanks appropriately. < μ < (round to 3 decimal places)
Complete Question
The complete question is shown on the first uploaded image
Answer:
The confidence interval is [tex]64.86<\mu<67[/tex]
Step-by-step explanation:
From the question we are given the following data
The following heights are
66, 65, 67, 62, 62, 65, 61, 70, 66, 66, 71, 63, 69, 65, 71, 66, 66, 69, 68, 62, 65, 67, 65, 71, 65, 70, 62, 62, 63, 64, 67, 67
The sample size is n =32
The confidence level is [tex]k = 95[/tex]% = 0.95
The mean is evaluated as
[tex]\= x = 66+ 65+ 67+ 62+ 62+ 65+ 61+ 70+ 66+ 66+ 71+63+ 69+ 65+ 71+ 66+ 66+ 69+ 68+ 62+ 65+ 67,+\\65+ 71+ 65+ 70+ 62+ 62+ 63+ 64+ 67+ 67 / 32[/tex]
=> [tex]\= x = \frac{2108}{32}[/tex]
=> [tex]\= x = 65.875[/tex]
The standard deviation is evaluated as
[tex]\sigma = \sqrt{ v}[/tex]
Now
[tex]v = ( 66-65.875 )^2+(65-65.875)^2+( 67-65.875)^2+ (62-65.875)^2+ (62-65.875)^2+ (65-65.875)^2+( 61-65.875)^2+ (70-65.875)^2+ (66-65.875)^2+ (66-65.875)^2+ (71+63-65.875)^2+ (69-65.875)^2+ (65-65.875)^2+ (71-65.875)^2+( 66-65.875)^2+ (66-65.875)^2+ (69-65.875)^2+ (68-65.875)^2+ (62-65.875)^2+ (65-65.875)^2+ (67-65.875)^2,+\\(65-65.875)^2+ (71-65.875)^2+ (65-65.875)^2+ (70-65.875)^2+( 62-65.875)^2+( 62-65.875)^2+ (63-65.875)^2+ (64-65.875)^2+ (67-65.875)^2+ (67-65.875)^2 / 32[/tex]
=>[tex]v= 8.567329[/tex]
=> [tex]\sigma = \sqrt{8.567329}[/tex]
=> [tex]\sigma = 2.927[/tex]
The level of significance is evaluated as
[tex]\alpha = 1 - 0.95[/tex]
[tex]\alpha = 0.05[/tex]
The degree of freedom is evaluated as
[tex]Df = n- 1 \equiv Df = 32 -1 = 31[/tex]
The critical values for the level of significance is obtained from the z -table as
[tex]t_c = t_{\alpha/2 } , Df = t _{0.05/2}, 31 =\pm 1.96[/tex]
The confidence interval is evaluated as
[tex]\mu = \= x \pm t_c * \frac{\sigma }{\sqrt{n} }[/tex]
substituting values
[tex]\mu =65.875 \pm 1.96* \frac{2.927}{\sqrt{32} }[/tex]
[tex]\mu =65.875 \pm 1.01415[/tex]
=> [tex]64.86<\mu<67[/tex]
Brian invests £8000 into his bank account. He receives 3% per year compound interest. How many years will it take for Brian to have more than £9500?
Answer:
6 years is the correct answer.
Step-by-step explanation:
Given that
Principal, P = £8000
Rate of interest, R = 3% compounding annually
Amount, A > £9500
To find: Time, T = ?
We know that formula for Amount when interest in compounding:
[tex]A = P \times (1+\dfrac{R}{100})^T[/tex]
Putting all the values:
[tex]A = 8000 \times (1+\dfrac{3}{100})^T[/tex]
As per question statement, A > £9500
[tex]\Rightarrow 8000 \times (1+\dfrac{3}{100})^T > 9500\\\Rightarrow (1+0.03)^T > \dfrac{9500}{8000}\\\Rightarrow (1.03)^T > 1.19[/tex]
Putting values of T, we find that at T = 6
[tex]1.03^6 = 1.194 > 1.19[/tex]
[tex]\therefore[/tex] Correct answer is T = 6 years
In 6 years, the amount will be more than £9500.