Candice is preparing for her final exam in Statistics. She knows she needs an 65 out of 100 to earn an A overall in the course. Her instructor provided the following information to the students. On the final, 200 students have taken it with a mean score of 57 and a standard deviation of 6. Assume the distribution of scores is bell-shaped. Calculate to see if a score of 65 is within one standard deviation of the mean.
Answer:
a. 72
b. 816
c. 570
d. 30
Step-by-step explanation:
Given the graph is a bell - shaped curve. So, we understand that this is a normal distribution and that the bell - shaped curve is a symmetric curve.
Please refer the figure for a better understanding.
a. In a normal distribution, Mean = Median = Mode
Therefore, Median = Mean = 72
b. We have to know that 68% of the values are within the first standard deviation of the mean.
i.e., 68% values are between Mean Standard Deviation (SD).
Scores between 63 and 81 :
Note that 72 - 9 = 63 and
72 + 9 = 81
This implies scores between 63 and 81 constitute 68% of the values, 34% each, since the curve is symmetric.
Now, Scores between 63 and 81 =
= 68 X 12 = 816.
That means 816 students have scored between 63 and 81.
c. We have to know that 95% of the values lie between second Standard Deviation of the mean.
i.e., 95% values are between Mean 2(SD).
Note that 90 = 72 + 2(9) = 72 + 18
Also, 54 = 63 - 18.
Scores between 54 and 90 totally constitute 95% of the values. So, Scores between 72 and 90 should amount to of the values.
Therefore, Scores between 72 and 90 =
= 570.
That is a total of 570 students scored between 72 and 90.
d. We have to know that 5 % of the values lie on the thirst standard Deviation of the mean.
In this case, 5 % of the values lie between below 54 and above 90.
Since, we are asked to find scores below 54. It should be 2.5% of the values.
So, Scores below 54 =
= 2.5 X 12 = 30.
That is, 30 students have scored below 54.
Step-by-step explanation:
It is found that score of 62 is not within one standard deviation of the mean.
What is z - score?The Z-score measures how many standard deviations the measure is from the mean. If we've got a normal distribution, then we can convert it to standard normal distribution and its values will give us the z score.
If we have [tex]X \sim N(\mu, \sigma)[/tex]then it can be converted to standard normal distribution as
[tex]Z = \dfrac{X - \mu}{\sigma}, \\\\Z \sim N(0,1)[/tex]
In a set with mean and standard deviation, the z- score of a measure X is given by:
[tex]Z = \dfrac{X - \mu}{\sigma},[/tex]
Z-score, we look at the z-score table and find the p-value associated with this z-score.
Given that Mean score of 54 and a standard deviation of 6.
This means to see if a score of 62 is within one standard deviation of the mean.
Is Z between -1 and 1 when X = 62.
[tex]Z = \dfrac{X - \mu}{\sigma},\\Z = \dfrac{62 - 54}{6},[/tex]
Z = 1.33
Therefore, It is found that score of 62 is not within one standard deviation of the mean.
Learn more about z-score here:
https://brainly.com/question/21262765
#SPJ2
Find the unknown angle measure.
Answer:
x=22
Step-by-step explanation:
180-77=103
103+55=158
180-158=22
x=22
LUCILLES PENCIL POUCH WOULD HOLD 3/8
OF THE 48 PENCILS THAT SHE PURCHASED AT
THE BEGINNING OF THE NEW SCHOOL YEAR.
HOW MANY PENCILS WILL FIT IN HER POUCH. will give brainlist
Answer:
18
Step-by-step explanation:
You would divide 48 by 8 and multiply it by 3. Otherwise, you could do
3/8 = x/48
x * 8 = 3 * 48
x * 8 = 144
/8 /8
x = 18
A farm has 56 horses and sheep in all. There are 8 fewer sheep than horses. How many horses are there on the farm?
Answer:
32 Horses
Step-by-step explanation:
32-8=24
There are 32 horses and 24 sheep (As you can see there are 8 fewer sheep than horses)
I sort of guess and checked:
I tried to think of 2 numbers that added to 56 but one number was 8 less than the other one.I figured out that 32 and 24 fit this description :)magazine subscription cost $29.88 for 12 issues or $15.28 for six issues which subscription cost more per issue
Answer:
$15.28 for 6 issues cost more
Step-by-step explanation:
$29.88 divided by 12 is $2.49
$15.28 divided by6 is $2.546
Show all your work. Indicate clearly the methods you use, because you will be scored on the correctness of your methods as well as on the accuracy and completeness of your results and explanations. The distribution of pH levels for all community swimming pools in a large county is approximately normal with mean 7.5 and standard deviation 0.2. According to swimming pool studies, the safest pH levels for water in swimming pools are between 7.2 and 7.8. (a) One community swimming pool in the county will be selected at random. What is the probability that the selected pool has a pH level that is not considered safe
Answer:
The value is [tex]P(A) = 0.133617[/tex]
Step-by-step explanation:
From the question we are told that
The mean is [tex]\mu = 7.5[/tex]
The standard deviation is [tex]\sigma = 0.2[/tex]
The safest water level is between 7.2 and 7.8
Generally the probability that the selected pool has a pH level that is not considered safe is mathematically represented as
[tex]P(A) = 1 - P(7.2 \le X \le 7.8 )[/tex]
Here
[tex]P(7.2 < X < 7.8 ) = P(\frac{ 7.2 - \mu }{\sigma } < \frac{X - \mu }{ \sigma } <\frac{ 7.8 - \mu }{\sigma } )[/tex]
Generally [tex]\frac{X - \mu }{ \sigma } = Z (The \ standardized \ value \ of X )[/tex]
So
[tex]P(7.2 < X < 7.8 ) = P(\frac{ 7.2 - 7.5 }{0.2 } < Z <\frac{ 7.8 - 7.5 }{0.2 } )[/tex]
[tex]P(7.2 < X < 7.8 ) = P(-1.5 < Z <1.5)[/tex]
=> [tex]P(7.2 < X < 7.8 ) = P(Z < 1.5) - P( Z < - 1.5) [/tex]
From the z-table the probability of (Z < -1.5) and ( Z <1.5) are
[tex]P(Z < 1.5) = 0.93319[/tex]
and
[tex]P(Z < -1.5) = 0.066807[/tex]
So
[tex]P(7.2 < X < 7.8 ) =0.93319 - 0.066807 [/tex]
[tex]P(7.2 < X < 7.8 ) =0.0866383[/tex]
So
[tex]P(A) = 1 - 0.0866383[/tex]
=> [tex]P(A) = 0.133617[/tex]
The probability that the selected pool has a pH level that is not considered safe pool is 0.1336
The given parameters are:
[tex]\mathbf{\mu = 7.5}[/tex]
[tex]\mathbf{\sigma = 0.2}[/tex]
Start by calculating the probability that a pool is safe.
This is represented as: P(7.2 < x < 7.8)
Calculate the z-scores for x =7.2 and 7.8 using:
[tex]\mathbf{z = \frac{x - \mu}{\sigma}}[/tex]
So, we have:
[tex]\mathbf{z = \frac{7.2 - 7.5}{0.2} = -1.5}[/tex]
[tex]\mathbf{z = \frac{7.8 - 7.5}{0.2} = 1.5}[/tex]
So, we have:
[tex]\mathbf{P(7.2 < x < 7.8) = P(-1.5 < z < 1.5)}[/tex]
This gives
[tex]\mathbf{P(7.2 < x < 7.8) = P(z < 1.5) - P(z < -1.5)}[/tex]
Using z table of probabilities, we have:
[tex]\mathbf{P(7.2 < x < 7.8) =0.9332 - 0.0668}[/tex]
[tex]\mathbf{P(7.2 < x < 7.8) =0.8664}[/tex]
The probability that the pool is not safe is calculated using the following complement formula
[tex]\mathbf{P(Not\ Safe) = 1 - P(Safe)}[/tex]
So, we have:
[tex]\mathbf{P(Not\ Safe) = 1 -0.8664}[/tex]
[tex]\mathbf{P(Not\ Safe) = 0.1336}[/tex]
Hence, the probability that the pool is not safe is 0.1336
Read more about probabilities at:
https://brainly.com/question/11234923
what is eighteen and three fourths divided by two and a half?
Answer:
the answer is 7.5
The graph below shows the elevation of three submarines during their first four minutes depending into the water which statement is true?
Answer:
ANSWER IS A I THINK
Step-by-step explanation:
Container A and container B have leaks. Container A has 800ml of water, and is leaking 6 ml per minute. Container B has1000 ml, and is leaking 10 ml per minute. How many minutes, m, will it take for the two containers to have the same amount of water?
Answer:
50 minutes
Step-by-step explanation:
First set up an inequality to find you answer like
800 - 6x = 1000 - 10x
then subtract 800 from both sides leaving you with
-6x = 200 - 10 x
Then add 10 x to both sides giving you
4x = 200
The simplify from here by dividing 200 by 4
200/4 = 50 giving you your answer
If x= 12 and y=3, what is the value of x-y²?
Answer:
3
Step-by-step explanation:
X=12 Y=3^2
Y^2=3x3 Which equals 9 therefore it is 12-9 which equals 3
Answer:
I believe the answer would be 3.
Step-by-step explanation:
I hope this helps
Simplify 2x^3 х 3x^2
Answer:
ans = 6x4
Step-by-step explanation:
(2x2)(3x2)
first multiply the coefficients
(2*3) = 6
next multiply the variables
(x2*x2) = x2+2 = x4
productofcoeficients,productofvariables
= 6x4
Help me plzzzzz
It’s late cuz I’m dum
8th grade math...
The answer is B
Hope this helps! i just learned this today lol
.60 is what percent of 180?
Answer:
1.08
Step-by-step explanation:
.60% *180=108
108/100=1.08%
Answer:
108
Step-by-step explanation:
an aquarium has display tanks that each contain 175 fish.how many fish are on display in 6 tanks
Answer:
1050 fish
Step-by-step explanation:
175(6 tanks) = 1050
Choose all pairs of points that are reflections of each other across both axes.
A. (–4 1/2, 1) and (–1, 4 1/2)
B. (2.5, –1) and (–2 1/2, 1)
C. (4.2, –1) and (2.4, –1)
D. (1, –2.25) and (–1, 2 1/4)
E. (–2, 2 1/3) and (2, 2 1/3)
Answer:
c
Step-by-step explanation:
Answer: C
Step-by-step explanation:
A survey of 1282 student loan borrowers found that 440 had loans totaling more than $20,000 for their undergraduate education. Give a 98% confidence interval for the proportion of all student loan borrowers who have loans of $20,000 or more for their undergraduate education. (Give answers accurate to 3 decimal places.)
Answer:
The 98% confidence interval of the proportion = (0.312, 0.374)
Step-by-step explanation:
(Give answers accurate to 3 decimal places.)
The formula for Confidence Interval of Proportion is given as:
p ± z × √p(1 - p)/n
Where p = Proportion = x/n
x = 440
n = 1282
p = 440/1282 = 0.34321372854
Approximately = 0.343
z = z-score of 98 % confidence interval
= 2.326
Confidence Interval =
= 0.343 ± 2.326 × √0.343(1 - 0.343)/1282
= 0.343 ± 2.326 × √0.225351/1282
= 0.343 ± 2.326 × √0.00017578081
= 0.343 ± 2.326 × 0.01325823555
= 0.343 ± 0.03083865589
0.343 - 0.03083865589
= 0.31216134411
Approximately = 0.312
0.343 + 0.03083865589
= 0.37383865589
Approximately to = 0.374
Therefore, the 98% confidence interval of the proportion = (0.312, 0.374)
It too Mrs. phillips 1.6 hours to run the 13.2 miles. What was his average speed
Answer:
13.2 miles/ 1.6 hours= 8.25 miles/hour.Mr. Phillips's speed was 8.25
Before adding the following fractions, you need to find the common ? 2/3 + 1/6 =
Answer:
denominator
Step-by-step explanation:
Answer:
5/6
Step-by-step explanation:
2/3×2/2 + 1/6
4/6 + 1/6
5/6
Riley and Rhoda plan to buy several bags of dog food and a dog collar. Each bag of dog food costs $7, and the dog collar cost $5
Answer:
2bags= $14 + $5
3bags= $21+ $5
4bags= $28 + $5
5bags= $35 + $5
6bags= $42 + $5
multiply # of bags by 7
and add $5
If 5% more than a is b, and b is 15% less than, what is the ratio of a to c? Please answer quickly.
Susie walk 10 miles each week. she has already walked 3 miles this week and expects to walk 100 miles how long will it take her to walk 100 miles
Answer:
10 weeks
Step-by-step explanation: 100÷10=10
big brain
Answer:
9 week and 4 days
Step-by-step explanation:
PLEASE HELP!!
Sorry for all the tabes I'm working on a presentation at the same time.
Answer:
0.5
Step-by-step explanation:
use rise over run, from (-6,0) to (0,3) it rises 3 and runs 6. 3/6 = 1/2.
Answer:
the slope is two
Step-by-step explanation:
rise over run
Which of the following equations is equivalent to 30 = 2 ( -2x + 6
Answer:
30=-4x+12
Step-by-step explanation:
they both equal -9/2
In a study using 50 foreign-language vocabulary words, the learning rate L (in words per minute) was found to depend on the number of words already learned, x, according to the equation L(x) = 20 – 0.4x
Here is the complete question
1. State coordinates of x axis
2. State coordinates of y axis
3. State the slope
4. Graph the function
5. Is learning rate increasing or decreasing?
Answer:
1. (50,0)
2. (0,20)
3. Slope = -0.4
4. Check attachment for graph
5. Learning rate is decreasing
Step-by-step explanation:
1.
L(x) = 20-0.4x
20 = 0.4x
x = 20/0.4
x = 50
(50,0)
2
For y coordinate;
L(0) = 20-0.4(0)
= 20
(0,20)
3.
Slope,
Y = -0.4x+20
We compare with
Y = mx+c
m = -0.4
Intercept c = 20
4. Check attachment
5. The slope is negative at m = -0.4 therefore the rate of learning is on a decline. As number of words learnt increases, learning rate falls.
Answer:
Step-by-step explanation:
PLEASE QUICK BRAINLISET
Answer: the answer is f
Answer:
F
Step-by-step explanation:
the measure of angle one must be equal to the measure of angle five and when doing the math I got x=34 plug that into the equation for angle five i got 48 and the same for plugging it into the equation for angle one.
Low‑density lipoprotein, or LDL, is the main source of cholesterol buildup and blockage in the arteries. This is why LDL is known as "bad cholesterol." LDL is measured in milligrams per deciliter of blood, or mg/dL. In a population of adults at risk for cardiovascular problems, the distribution of LDL levels is normal, with a mean of 123 mg/dL and a standard deviation of 41 mg/dL. If an individual's LDL is at least 1 standard deviation or more above the mean, he or she will be monitored carefully by a doctor. What percentage of individuals from this population will have LDL levels 1 or more standard deviations above the mean?
Answer:
The percentage of individuals from this population will have LDL levels 1 or more standard deviations above the mean is 16%.
Step-by-step explanation:
Let X represent the LDL levels.
It is provided that [tex]X\sim N(123, 41^{2})[/tex].
Compute the probability that a randomly selected individual is will have LDL levels 1 or more standard deviations above the mean as follows:
[tex]P(X\geq \mu+\sigma)=P(X\geq 123+41)[/tex]
[tex]=P(X\geq 164)\\\\=P(\frac{X-\mu}{\sigma}\geq \frac{164-123}{41})\\\\=P(Z>1)\\\\=1-P(Z<1)\\\\=1-0.84134\\\\=0.15866\\\\\approx 0.16[/tex]
Thus, the percentage of individuals from this population will have LDL levels 1 or more standard deviations above the mean is 16%.
7th grade math help me plzzzz
Answer:
b, c, f are coorrect inequalities
Step-by-step explanation:
hope i helped :D
Anna is in a cave 42 feet below the cave entrance. She descends 10 feet, then ascends 15 feet. Find her new position relative to the cave entrance.
Answer:
Her new position is 37 feet below the cave entrance
Step-by-step explanation:
Let us solve the question
∵ The cave entrance is the zero position
∵ Anna is in 42 feet below the cave entrance
→ Below zero means negative
∴ Anna is in -42 feet
∵ She descends 10 feet
→ Descend means negative
∴ She is in -42 + -10 = -52 feet
∵ She ascends 15 feet
→ Ascend means positive
∴ She is in -52 + 15 = -37 feet
→ -37 means she is in below the cave entrance by 37 feet
∴ Her new position is 37 feet below the cave entrance
Help. (Math) The following construction was performed. What distance did the compass have to be set to sweep the two arcs through point T?
1. RP
2. QR
3. QT
4. QP
Wade picked 4 pints of blackberries. His friend, Matt, picked 6 pints. How
many pints did they pick altogether?