Step-by-step explanation:
Let y1 and y2 be (e^x)/2, and (xe^x)/2 respectively.
The Wronskian of them functions be
W = (y1y2' - y1'y2)
y1 = (e^x)/2 = y1'
y2 = (xe^x)/2
y2' = (1/2)(x + 1)e^x
W = (1/4)(x + 1)e^(2x) - (1/4)xe^(2x)
= (1/4)(x + 1 - x)e^(2x)
W = (1/4)e^(2x)
Since the Wronskian ≠ 0, we conclude that functions are linearly independent, and hence, form a set of fundamental solutions.
Answer:
W = (1/4)(x + 1)e^(2x) - (1/4)xe^(2x)
= (1/4)(x + 1 - x)e^(2x)
W = (1/4)e^(2x)
Step-by-step explanation:
Halfway through the season, a soccer player has made 15 penalty kicks in 19 attempts. Based on her performance to date, what is the relative frequency probability that she will make her next penalty kick?
Answer:
[tex]\dfrac{15}{19}[/tex]
Step-by-step explanation:
The soccer player so far has made 15 penalty kicks in 19 attempts.
Therefore:
Total Number of trials =19
Number of Successes =15
Therefore, the relative frequency probability that she will make her next penalty kick is:
[tex]=\dfrac{\text{Number of Successes}}{\text{Total Number of Trials}} \\=\dfrac{15}{19}[/tex]
A baseball player swings and hits a pop fly straight up in the air to the catcher. The height of the baseball in meters t seconds after it is hit is given by the quadratic function h(t)= -4.9t^2 + 9.8t + 1. How long does it take for the baseball to reach its maximum height? What is the maximum height obtained by the baseball?
Answer:
Step-by-step explanation:
max can be found by the formula:
t=-b/2a
t=-9.8/2*(-4.9)
t=-9.8/-9.8
t=1
1 sec
to find maximum height obtained we find the vertex:
plug in 1 for t and simply solve:
h(t)= -4.9t^2 + 9.8t + 1
h(t)= -4.9*1^2 + 9.8*1 + 1
h(t)= -4.9*1 + 9.8 + 1
h(t)= -4.9 + 10.8
h(t)= 5.9
height is 5.9
Find the volume of the rectangular prism.
8 ft
8 ft
8 ft
Answer:
V = 512 ft^3
Step-by-step explanation:
The volume of a prism is length * width * height
V = 8*8*8
V = 512 ft^3
The volume of a rectangular prism is lwh.
V=lwh
V=8*8*8
V=8^3
V=512
IT IS EXTREAMLY URGENT!!! I WILL GIVE BRANLIEST!!!!AT LEAST TAKE A LOOK!!!!!! HELPPPPPPPPP
Find the value of x in the figure below. (Round your answer to the nearest whole number)
A) 5 inches
B) 7 inches
C) 6 inches
D) 8 inches
YOU HAVE TO CLICK THE TRIANGLE TO EE IT BETTER, JUST IN CASE ON THE TOP LEFT SIDE IT IS 8IN AND THE BOTTOM OF THE TRIANGLE IS 10 IN
Answer: D) 8 inches
====================================================
Work Shown:
Refer to the diagram below.
A = 50 degrees
B = unknown
C = 80 degrees
-----
For any triangle, the three angles always add to 180
A+B+C = 180
50+B+80 = 180
B+130 = 180
B = 180-130
B = 50 degrees
Since angles B and C are the same measure, their opposite sides are the same length. Triangle ABC is isosceles. Therefore, a = x = 8
Answer: D) 8 inches.
Step-by-step explanation: The triangle has three angles: two were given (50º and 80º) and the other one can be calculated (50º). Therefore, this triangle is an isosceles triangle, it has one base and two congruent sides. Since the one side is 8in, then the other missing side must also be 8in according to the Isosceles Triangle Theorem.
Fill out the tables for each scenario and answer the question that follows. Use $7.25 as the minimum wage and remember that employees in the United States must be paid time-and-a-half (1.5 times the normal hourly rate) for each hour worked over 40 hours per week
Answer:
see below for the table valuesUS labor cost: $115275 per yearStep-by-step explanation:
The labor charge is for (6 days/week). In Mongolia, the charge per laborer is then ...
(6 days/week)($1.10/day) = $6.60/week
The three laborers working 50 weeks/year will have a labor cost of ...
(3 laborers)($6.60/week/laborer)(50 weeks/year) = $990/year
__
In the US, the labor charge per person per week is ...
(14 hr/day)(6 day/week) = 84 hr/week
That's 40 hours of straight pay and 44 hours of overtime pay, or ...
7.25(40 +1.5(44)) = 7.25(106) = 768.50
For 150 person-weeks per year, the total US labor charge is ...
($768.50/person/week)(3 persons)(50 weeks/year) = $115,275/year
__
The materials cost for a year is ...
($50/rug)(12 rugs/year) = $600/year
__
The revenue is ...
($2000/rug)(12 rugs/year) = $24,000/year
Profit is the difference between revenue and the total of costs:
profit = $24,000 -($990 +600 +10000) = $12410 . . . made in Mongolia
__
So, the table gets filled as follows:
(labor, material, fixed cost, revenue, profit)
Mongolian-made
($990, $600, $10000, $24000, $12410)
US-made
($115275, $600, $10000, $24000, -$101,875)
The US labor cost would be $115,275.
_____
Comment
For the given selling price, the break-even labor cost is about $1.06 per hour (on average). At US labor rates, the break-even selling price is about $10,490 per rug.
please very soon I offer the crown !!! + 10 points urgently !!!
Find the slope of the line graphed above. Question 2 options: A) –6 B) –10 C) –8 D) –5
Answer: -6
Step-by-step explanation: The slope of a line is rise divided by run. This is shown by the equation (y2-y1) / (x2-x1) = slope of a line.
For this specific line you can plug in two points such as (2,-4) and (1,2)
[2-(-4)] / (1-2) = -6
Hope this helps :)
The probability that a person in the United States has type B+ blood is 12%. Three unrelated people in the United States are selected at random. Complete parts (a) through (d). (a) Find the probability that all three have type B+ blood. The probability that all three have type B+ blood is nothing. (Round to six decimal places as needed.)
Answer:
The probability that all three have type B+ blood is 0.001728
Step-by-step explanation:
For each person, there are only two possible outcomes. Either they have type B+ blood, or they do not. The probability of a person having type B+ blood is independent of any other person. 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.
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.
[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]
And p is the probability of X happening.
The probability that a person in the United States has type B+ blood is 12%.
This means that [tex]p = 0.12[/tex]
Three unrelated people in the United States are selected at random.
This means that [tex]n = 3[/tex]
Find the probability that all three have type B+ blood.
This is P(X = 3).
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 3) = C_{3,3}.(0.12)^{3}.(0.88)^{0} = 0.001728[/tex]
The probability that all three have type B+ blood is 0.001728
Jaden had 2 7/16 yards of ribbon. He used 1 3/8 yards of ribbon to make a prize ribbon. How much does he have now?
EASY!
Answer: 17/16 or 1 1/16
Step-by-step explanation:
BRO IT'S ELEMANTARY FRACTIONS!!!!
An airport limousine can accommodate up to four passengers on any one trip. The company will accept a maximum of six reservations for a trip, and a passenger must have a reservation. From previous records, 30% of all those making reservations do not appear for the trip. Answer the following questions, assuming independence wherever appropriate. (Round your answers to three decimal places.)
(a) If six reservations are made, what is the probability that at least one individual with a reservation cannot be accommodated on the trip?
(b) If six reservations are made, what is the expected number of available places when the limousine departs?
Answer:
(a) The probability that at least one individual with a reservation cannot be accommodated on the trip is 0.4202.
(b) The expected number of available places when the limousine departs is 0.338.
Step-by-step explanation:
Let the random variable Y represent the number of passenger reserving the trip shows up.
The probability of the random variable Y is, p = 0.70.
The success in this case an be defined as the number of passengers who show up for the trip.
The random variable Y follows a Binomial distribution with probability of success as 0.70.
(a)
It is provided that n = 6 reservations are made.
Compute the probability that at least one individual with a reservation cannot be accommodated on the trip as follows:
P (At least one individual cannot be accommodated) = P (X = 5) + P (X = 6)
[tex]={6 \choose 5}\ (0.70)^{5}\ (1-0.70)^{6-5}+{6 \choose 6}\ (0.70)^{6}\ (1-0.70)^{6-6}\\\\=0.302526+0.117649\\\\=0.420175\\\\\approx 0.4202[/tex]
Thus, the probability that at least one individual with a reservation cannot be accommodated on the trip is 0.4202.
(b)
The formula to compute the expected value is:
[tex]E(Y) = \sum X\cdot P(X)[/tex]
[tex]P (X=0)={6 \choose 0}\ (0.70)^{0}\ (1-0.70)^{6-0}=0.000729\\\\P (X=1)={6 \choose 1}\ (0.70)^{1}\ (1-0.70)^{6-1}=0.010206\\\\P (X=2)={6 \choose 2}\ (0.70)^{2}\ (1-0.70)^{6-2}=0.059535\\\\P (X=3)={6 \choose 3}\ (0.70)^{3}\ (1-0.70)^{6-3}=0.18522\\\\P (X=4)={6 \choose 4}\ (0.70)^{4}\ (1-0.70)^{6-4}=0.324135[/tex]
Compute the expected number of available places when the limousine departs as follows:
[tex]E(Y) = \sum X\cdot P(X)[/tex]
[tex]=(4\cdot 0.000729)+(3\cdot 0.010206)+(2\cdot 0.059535)+(1\cdot 0.18522)\\+(0\cdot 0.324135)\\\\=0.002916+0.030618+0.11907+0.18522+0\\\\=0.337824\\\\\approx 0.338[/tex]
Thus, the expected number of available places when the limousine departs is 0.338.
eBookThe manager of the Danvers-Hilton Resort Hotel stated that the mean guest bill for a weekend is or less. A member of the hotel's accounting staff noticed that the total charges for guest bills have been increasing in recent months. The accountant will use a sample of future weekend guest bills to test the manager's claim.a. Which form of the hypotheses should be used to test the manager's claim
Answer:
Step-by-step explanation:
The question is incomplete. The complete question is
The manager of the Danvers-Hilton Resort Hotel stated that the mean guest bill for a weekend is $600 or less. A member of the hotel’s accounting staff noticed that the total charges for guest bills have been increasing in recent months. The accountant will use a sample of
weekend guest bills to test the manager’s claim.
a. Which form of the hypotheses should be used to test the manager’s claim? Explain.
1) H0:μ ≥ 600
Ha:μ < 600
2) H0:μ ≤ 600
Ha:μ > 600
3) H0:μ=600
Ha:μ≠600
b. What conclusion is appropriate when H0 cannot be rejected?
c. What conclusion is appropriate when H0 can be rejected?
Solution:
a) the hypotheses should be used to test the manager’s claim is
H0:μ ≤ 600
Ha:μ > 600
This is because the already known or assumed mean guest bill for a weekend is 600 or less. This forms the null hypothesis. The alternative is the opposite of the null hypothesis. Since the alternative states that it is increasing, the sign,> would be used.
b) If H0 cannot be rejected, it means that there is no sufficient evidence to reject H0 at the given level of significance.
c) if H0 can be rejected, it means that there is sufficient evidence to reject H0 at the given level of significance.
Graph g(x)=-2|x-5|-4
Answer:
Step-by-step explanation:
Use the multiplication rule for independent event probabilities. Two friends are both pregnant, and find out they are each expecting twins! Let A be the event that one friend is pregnant with identical twins, and note that P(A) = 0.0045. Let B be the event that the other friend is pregnant with fraternal twins, and note that P(B)= 0.01. A and B are independent events. What is the probability that one friend is pregnant with identical twins, and one friend is pregnant with fraternal twins? Give your answer as a percent, rounded to four decimal places if necessary.
Answer:
We have to multiply P(A) and P(B) which is 0.0045 * 0.01 * 100 (to make it a percentage) = 0.0045%.
According to the diagram, a 13-foot ladder leans against a 12-foot wall. The distance from the base of the wall is 5 feet. Based on this information, which trigonometric ratio has the value of 12/5
Answer:
Tangent
Step-by-step explanation:
if the angle in question is the bottom of the ladder and the ground, then tangent is opposite over adjacent... or 12/5
Hope this is right
Find the scale ratio for the map described below.
1 mm (map)equals500 m (actual)
The scale ratio is 1 to
nothing.
Answer:
The answer is nothing duh
Step-by-step explanation:
PLEASE HELP!
A farmer wanted to paint a shed out in his field. Here is the breakdown of the dimensions: the building is sitting on a square slab of cement that is 10' x 10'. It is 8 feet from the bottom of the shed to the bottom of the roof on the edge, and 10 feet from the bottom of the shed to the top of the very tip top of the roof. So A = 10, B = 8 and C = 10. Using the formula for the area of a rectangle, A = l x w and the area of a triangle, 1/2(bh), b is base and h is height, then find the total area that needs to be painted. Total area =
Answer:
340 square feet
Step-by-step explanation:
If we "unwrap" the painted surface from the shed, it will have the shape shown in the attachment. It is essentially a 40' by 8' rectangle with two 10' wide by 2' high triangles added.
The rectangle area is ...
A = LW = (40 ft)(8 ft) = 320 ft²
The total area of the two triangles is ...
A = 2(1/2)bh = (10 ft)(2 ft) = 20 ft²
Then the painted area is ...
total area = 320 ft² +20 ft²
total area = 340 ft²
How many cubes with side lengths of end fraction 1/2 cm does it take to fill the prism? btw anyone who answers this first will be marked the brainiest answer and get a thanks from me :)
Need help please guysssssss
Answer:
C
Step-by-step explanation:
3x+2-x>8
2x+2>8
2x>8-2
2x>6
x>3
Answer:
C
Step-by-step explanation:
Assume that a procedure yields a binomial distribution with a trial repeated n times. Use the binomial probability formula to find the probability of x successes given the probability p of success on a single trial.
n=55,
x=33,
p=0.55
p(3)=_________
Answer:
P(33) = 0.0826
Step-by-step explanation:
The binomial distribution in this case has parameters n=55 and p=0.55.
The probability that k successes happen with these parameters can be calculated as:
[tex]P(x=k) = \dbinom{n}{k} p^{k}(1-p)^{n-k}\\\\\\P(x=k) = \dbinom{55}{k} 0.55^{k} 0.45^{55-k}\\\\\\[/tex]
We have to calculate the probability fo X=33 succesess.
This can be calculated using the formula above as:
[tex]P(x=33) = \dbinom{55}{33} p^{33}(1-p)^{22}\\\\\\P(x=33) =1300853625660220*0.0000000027*0.0000000235\\\\\\P(x=33) =0.0826\\\\\\[/tex]
Make the appropriate conclusion. Choose the correct answer below. A. RejectReject H0. There is insufficientinsufficient evidence at the alphaαequals=0.100.10 level of significance to conclude that the true mean heart rate during laughter exceeds 7171 beats per minute. B. Do not rejectDo not reject H0. There is insufficientinsufficient evidence at the alphaαequals=0.100.10 level of significance to conclude that the true mean heart rate during laughter exceeds 7171 beats per minute. C. RejectReject H0. There is sufficientsufficient evidence at the alphaαequals=0.100.10 level of significance to conclude that the true mean heart rate during laughter exceeds 7171 beats per minute. D. Do not rejectDo not reject H0. There is sufficientsufficient evidence at the alphaαequals=0.100.10 level of significance to conclude that the true mean heart rate during laughter exceeds 7171 beats per minute.
Answer:
a) Option D is correct.
H0: μ = 71
Ha: μ > 71
b) Option F is correct
z > 1.28
c) z = 2.85
d) Option C is correct.
Reject H0.There is sufficient evidence at the α = 0.10 level of significance to conclude that the true mean heart rate during laughter exceeds 71 beats per minute.
Step-by-step explanation:
a) For hypothesis testing, the first thing to define is the null and alternative hypothesis.
The null hypothesis plays the devil's advocate and usually takes the form of the opposite of the theory to be tested. It usually contains the signs =, ≤ and ≥ depending on the directions of the test.
While, the alternative hypothesis usually confirms the the theory being tested by the experimental setup. It usually contains the signs ≠, < and > depending on the directions of the test.
This question aims to test the the true mean heart rate during laughter exceeds 71 beats per minute.
Hence, the null hypothesis is that there isn't sufficient evidence to say that the true mean heart rate during laughter exceeds 71 beats per minute. That is, the true mean doesn't exceed 71 beats per minute.
And the alternative hypothesis is that there is sufficient evidence to say that the true mean heart rate during laughter exceeds 71 beats per minute.
Mathematically,
The null hypothesis is represented as
H₀: μ = 71
The alternative hypothesis is represented as
Hₐ: μ > 71
b) Using z-distribution, the rejection area is obtained from the confidence level at which the test is going to be performed. Since the hypothesis test tests only in one direction,
Significance level = (100% - confidence level)/2
0.10 = 10% = (100% - confidence level)/2
20% = 100% - (confidence level)
Confidence level = 100% - 20% = 80%
Critical value for 80% confidence level = 1.28
And since we are testing if the true mean heart rate during laughter exceeds 71 beats per minute, the rejection area would be
z > 1.28
c) The test statistic is given as
z = (x - μ)/σₓ
x = sample mean = 73.4
μ = 71
σₓ = standard error = (σ/√n)
σ = 8
n = Sample size = 90
σₓ = (8/√90) = 0.8433
z = (73.4 - 71) ÷ 0.8433
z = 2.846 = 2.85
d) Since the z-test statistic obtained, 2.85, is firmly in the rejection area, z > 1.28, we reject the null hypothesis, accept the alternative hypothesis and say that there is sufficient evidence at the α = 0.10 level of significance to conclude that the true mean heart rate during laughter exceeds 71 beats per minute.
Hope this Helps!!!
What is the area of the trapezoid below? Select one: a. 88 cm2 b. 44√3 cm2 c. 65 cm2 d. 36√3 cm2
Answer: D
Step-by-step explanation:
Since we are not given the height of the trapezoid, we can split this into a triangle and a rectangle. We find the area of each and then add them together. In order to do so, we must use Pythagorean Theorem to find the missing length so that we can find the area.
a²+b²=c²
a²+4²=8²
a²+16=64
a²=48
a=√48
a=4√3
Now that we know the missing length of the triangle, we can find the area of the triangle and the rectangle.
Triangle
A=1/2bh
A=1/2(4)(4√3)
A=8√3
-----------------------------------------------------------------------------------------
Rectangle
A=lw
A=7(4√3)
A=28√3
With our areas, we can add them together.
4√3+28√3=36√3 cm²
a painter paints the side of a house at a rate of 3 square feet per minute. if the dimensions of the side of the house are 15 feet by 18, how many minutes does it take the painter to finish the job?
Answer: 90 minutes
Step-by-step explanation:
Area of the side = 15 x 18 = 270 sq. ft.
3 sq. ft take a minute to paint
270 sq. ft. will take 270 / 3
= 90 minutes
A corporation must appoint a​ president, chief executive officer​ (CEO), chief operating officer​ (COO), and chief financial officer​ (CFO). It must also appoint a planning committee with four different members. There are 13 qualified​ candidates, and officers can also serve on the committee. A. How many different ways can the officers be​ appointed?B. How many different ways can the committee be​ appointed?
C. What is the probability of randomly selecting the committee members and getting the four youngest of the qualified​candidates?
Answer:
A) 715 ways
B) 715 ways
C) (1/715)
Step-by-step explanation:
This is a permutation and combination problem.
Since we want to select a number of people from a larger number of people, we use combination as the order of selection isn't important now.
A) How many different ways can the officers be appointed?
There are 4 officer positions.
There are 13 people in total.
We want to select 4 people from 13
Number of ways to select 4 people from 13 = ¹³C₄ = 715
B) How many different ways can the committee be appointed?
Number of committee members = 4
Total number of people available = 13
Number of ways to select 4 people from 13 = ¹³C₄ = 715
C) What is the probability of randomly selecting the committee members and getting the four youngest of the qualified candidates?
Selecting a group of the youngest candidates is just 1 amongst the total number of ways the 4 committee members can be picked,
Hence, the required probability = (1/715)
Hope this Helps!!!
Management at a home improvement store randomly selected 45 customers and observed their shopping habits. They recorded the number of items each of the customers purchased as well as the total time the customers spent in the store. Identify the types of variables recorded by the managers of the home improvement store.
Answer:
c. number of items - discrete; total time - continuous
Step-by-step explanation:
The question is incomplete due to the lack of the following options:
to. number of items - continuous; total time - discrete
b. number of items - continuous; total time - continuous
c. number of items - discrete; total time - continuous
d. number of items - discrete; total time - discrete
Knowing this, the type of variables recorded by managers of the home improvement store are,
c. number of items - discrete; total time - continuous
Discrete variables are those that are well defined and in the finite set of values and continuous variables are variables that can take a value between any of the other two values.
find the quotient of (5+4i)/(6+8i) ans express in simplest forms
Answer:
Your correct answer is 31/50 + -4/25 i
Step-by-step explanation:
5+4i/6+8i = 31/50 + -4/25 i
the number 312 lies between the perfect cubes what are they
Answer:
216-343
Step-by-step explanation:
the number 312 lies between 125 and 330
Surface area of a cylinder: S = 2ar+2arh , solve for h.
Answer:
[tex]h = \frac{s - 2ar}{2ar} \\ [/tex]
Step-by-step explanation:
[tex]s = 2ar + 2arh \\ s - 2ar = 2arh \\ \frac{s - 2ar}{2ar} = \frac{2arh}{2ar} \\ h = \frac{s - 2ar}{2ar} [/tex]
hope this helps you
brainliest appreciated
good luck! have a nice day!
Please answer this correctly
Answer:
the correct answer is
Step-by-step explanation:
So, the probability is:P(greater than 4)=26=13. This is a theoretical probability, which is the observed number of favorable outcomes out of a certain number of trials. For instance, suppose you rolled the six-sided die five times, and got the following results:2,6,4,5,6
hope this help you!!!!!
Answer:
1/5 chance.
Step-by-step explanation:
There is only one number, 5, that is greater than 4 and there are 5 total numbers so there is a 1/5 chance selecting that number.
Renee is making a scale diagram of her MP3 player. The length of her scale drawing is 8 inches, and the width is 14 inches. The actual length of the MP3 player is 4 centimeters, and the width is 7 centimeters. This is , and the scale factor is .
Answer:
2
Step-by-step explanation:
Scale Factor = [tex]\frac{AnySideOfDiagram}{AnySideOfMP3Player}[/tex]
So,
Scale Factor = [tex]\frac{8}{4} = \frac{14}{7}[/tex] = 2
So,
The scale factor is 2
The blood platelet counts of a group of women have a bell-shaped distribution with a mean of 255.4 and a standard deviation of 63.9. (All units are 1000 cells/muL.) Using the empirical rule, find each approximate percentage below. a. What is the approximate percentage of women with platelet counts within 3 standard deviations of the mean, or between 63.7 and 447.1? b. What is the approximate percentage of women with platelet counts between 191.5 and 319.3?
Answer:
a) From the empirical rule we know that within 3 deviations from the mean we have 99.7% of the data
b) [tex] P(191.5<X<319.5)[/tex]
We can find the number of deviations from the mean for the limits using the z score formula given by:
[tex]z=\frac{x-\mu}{\sigma}[/tex]
And replacing we got:
[tex] z=\frac{191.5-255.4}{63.9}= -1[/tex]
[tex] z=\frac{319.3-255.4}{63.9}= 1[/tex]
So we have values within 1 deviation from the mean and using the empirical rule we know that we have 68% of the values for this case
Step-by-step explanation:
For this case we have the following properties for the random variable of interest "blood platelet counts"
[tex]\mu = 255.4[/tex] represent the mean
[tex]\sigma = 63.9[/tex] represent the population deviation
Part a
From the empirical rule we know that within 3 deviations from the mean we have 99.7% of the data
Part b
We want this probability:
[tex] P(191.5<X<319.5)[/tex]
We can find the number of deviations from the mean for the limits using the z score formula given by:
[tex]z=\frac{x-\mu}{\sigma}[/tex]
And replacing we got:
[tex] z=\frac{191.5-255.4}{63.9}= -1[/tex]
[tex] z=\frac{319.3-255.4}{63.9}= 1[/tex]
So we have values within 1 deviation from the mean and using the empirical rule we know that we have 68% of the values for this case