Answer:
This type of sample can be best described as a stratified sample
Step-by-step explanation:
Samples may be classified as:
Convenient: Sample drawn from a conveniently available pool.
Random: Basically, put all the options into a hat and drawn some of them.
Systematic: Every kth element is taken. For example, you want to survey something on the street, you interview every 5th person, for example.
Cluster: Divides population into groups, called clusters, and each element in the cluster is surveyed.
Stratified: Also divides the population into groups. However, then only some elements of the group are surveyed.
In this question:
The students are divided into groups, according to how many years they have attended the university. Then, from each group, some(30) students are surveyed. This is an example of Statrified Sampling
What is the equation of a parabola with vertex (-5,6) and a=3
A y = 3(x + 5)2 – 6
By= 3(x + 5)2 + 6
y = 5(x - 3)2 – 6
Dy=3(x - 6)2 – 5
Answer:
Step-by-step explanation:
y = 3(x+5)² +6
In a test for ESP (extrasensory perception), a subject is told that cards the experimenter can see but the subject cannot contain a star, a circle, a wave, a triangle or a square. As the experimenter looks at each card in turn, the subject names the shape on the card. A subject who is just guessing has a one in four chance of guessing correctly on each card.
A. The count of correct guesses in 20 cards has a binomial distribution. What are n and p?
B. What is the mean number of correct guesses in 20 cards for subjects who are just guessing?
C. What is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?
Answer:
a) [tex]n = 20[/tex] and [tex]p = 0.25[/tex]
b) The mean number of correct guesses in 20 cards for subjects who are just guessing is 5.
c) 0.2023 = 20.23% probability of exactly 5 correct guesses in 20 cards if a subject is just guessing
Step-by-step explanation:
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 expected value of the binomial distribution is:
[tex]E(X) = np[/tex]
The standard deviation of the binomial distribution is:
[tex]\sqrt{V(X)} = \sqrt{np(1-p)}[/tex]
A. The count of correct guesses in 20 cards has a binomial distribution. What are n and p?
20 cards mean that [tex]n = 20[/tex]
A subject who is just guessing has a one in four chance of guessing correctly on each card, which means that [tex]p = \frac{1}{4} = 0.25[/tex]
B. What is the mean number of correct guesses in 20 cards for subjects who are just guessing?
Expected value, so
[tex]E(X) = np = 20*0.25 = 5[/tex]
The mean number of correct guesses in 20 cards for subjects who are just guessing is 5.
C. What is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?
This is P(X = 5). So
[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]
[tex]P(X = 5) = C_{20,5}.(0.25)^{5}.(0.75)^{15} = 0.2023[/tex]
0.2023 = 20.23% probability of exactly 5 correct guesses in 20 cards if a subject is just guessing
In a statistics class, 10 scores were randomly selected with the following results: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66. What are the lower and upper limits of a box-and-whiskers display of this data
Answer:
[tex]L =52[/tex] --- Lower Limit
[tex]U =82[/tex] --- Upper Limit
Step-by-step explanation:
Given
[tex]N = 10[/tex]
[tex]Data: 74, 73, 77, 77, 71, 68, 65, 77, 67, 66[/tex]
Required
Determine the lower and upper limits of box and whisker display
First, arrange the data in ascending order
The sorted data is:
[tex]Data: 65, 66, 67, 68, 71, 73, 74, 77, 77, 77[/tex]
The lower limit (L) is calculated using:
[tex]L = Q_1 - 1.5 * (Q_3-Q_1)[/tex]
The upper limit (U) is calculated using:
[tex]U =Q_3 + 1.5 * (Q_3-Q_1)[/tex]
Q1 is calculated using:
[tex]Q_1 = \frac{1}{4}(N+1)[/tex]
[tex]Q_1 = \frac{1}{4}(10+1) = 2.75 = 3rd\ data[/tex]
[tex]Q_1 = 67[/tex]
Q3 is calculated using:
[tex]Q_3 = \frac{3}{4}(N+1)[/tex]
[tex]Q_3 = \frac{3}{4}(10+1) = 8.25= 8th\ data[/tex]
[tex]Q_3 = 77[/tex]
So:
[tex]L = Q_1 - 1.5 * (Q_3-Q_1)[/tex]
[tex]L =67 - 1.5*(77-67)[/tex]
[tex]L =67 - 1.5*10[/tex]
[tex]L =67 - 15[/tex]
[tex]L =52[/tex]
[tex]U =Q_3 + 1.5 * (Q_3-Q_1)[/tex]
[tex]U =67 + 1.5*(77-67)[/tex]
[tex]U =67 + 1.5*10[/tex]
[tex]U =67 + 15[/tex]
[tex]U =82[/tex]
The population of a certain species of insect is given by a differentiable function P, where P(t) is the number of insects in the population, in millions, at time t, where t is measured in days. When the environmental conditions are right, the population increases with resect to time at a rate that is directly proportional to the population. Starting August 15, the conditions were favorable and the. population began increasing. On August 20, five days later, there were an estimated 10 million insects and the population was increasing at a rate of 2 million insects per day.
Required:
What is the differential equation that models this situation?
Answer:
[tex]\frac{dP}{dt} \ =\ \frac{1}{5}P[/tex]
Step-by-step explanation:
Given
Variation: Directly Proportional
Insects = 10 million when Rate = 2 million
i.e. [tex]P = 10\ million[/tex] when [tex]\frac{dP}{dt} = 2\ million[/tex]
Required
Determine the differential equation for the scenario
The variation can be represented as:
[tex]\frac{dP}{dt} \ \alpha\ P[/tex]
Which means that the rate at which the insects increase with time is directly proportional to the number of insects
Convert to equation
[tex]\frac{dP}{dt} \ =\ k * P[/tex]
[tex]\frac{dP}{dt} \ =\ kP[/tex]
Substitute values for [tex]\frac{dP}{dt}[/tex] and P
[tex]2\ million = k * 10\ million[/tex]
Make k the subject
[tex]k = \frac{2\ million}{10\ million}[/tex]
[tex]k = \frac{2}{10}[/tex]
[tex]k = \frac{1}{5}[/tex]
Substitute [tex]\frac{1}{5}[/tex] for k in [tex]\frac{dP}{dt} \ =\ k * P[/tex]
[tex]\frac{dP}{dt} \ =\ \frac{1}{5}* P[/tex]
[tex]\frac{dP}{dt} \ =\ \frac{1}{5}P[/tex]
Solve the equation: 3x - 2/4 = 2x – 8 Explain your reasoning / show work:
In Sahara Desert one day it was 130°F. In the Gobi Desert a temperature of -40°F was recorded. What is the difference between these two temperatures?
Answer: 170 degree difference
Answer:
The difference between two numbers canbbe obtained substracting.
The diffence between 130 °F and -40 °F would be the same as substracting both numebrs (we should put an absolute value as the difference is positive).
130 - (-40) = 130 + 40 = 170 ° F
So the difference is of 179 °F
PLEASE HELPP! WORTH 20 POINTS
For each situation described for a given linear model, is there a correlation? If
so, is there a causal correlation? Explain.
1. the number of minutes studied for a test and the final test grade
2. the attendance at a baseball game and number of runs the home team scores
in the game
Answer:
B
Step-by-step explanation:
Because
Negative fourty-eight and fifteenth thousand in decimal form
Answer:
-48.015
Step-by-step explanation
11a + 22 + 17a - 6 S I M P L I F I E D
Answer:
28a +16
Step-by-step explanation:
11a + 22 + 17a - 6
28a +16
Answer:
28a + 16
Step-by-step explanation:
Combine like terms. Like terms are terms with the same variables, as well as same amount of that variable.
In this case:
11a + 17a + 22 - 6
(11a + 17a) + (22 - 6)
28a + 16
28a + 16 is your answer.
~
What is 12% of 507
OA. 6
OB.
7
O c.
10
OD
12
A savings account increases from $150 to $159. What is the percent increase of the savings account?
Answer:
6%
Step-by-step explanation:
it increased by 9/150 = 0.06 = 6%
An isosceles right triangle has a hypotenuse that measures 32 inches. To the nearest inch,
what is the measure of each leg of the triangle?
Answer:
28 inch or 27.7 inch
other side is 16 inch
Step-by-step explanation:
We double the triangle and find each hypotenuse for two triangles to determine base as equilateral
32^2 = base
To find height we half base and multiply by slant = 32 inches
32/2 = 16 inch
Height = 32^2 - 16^2 = a^2 = sq rt 1024 - sqrt 256 = sq rt 768
a^2 = sq rt 768 = 27.7128129 = 28 inch or 27.7 inch
50 POINTS AND MARKED BRAINLIEST IF U DO THIS ASAP!
LOOK AT PICTURE
Answer:
Diagram 2, 12 foul balls
Step-by-step explanation:
12/3=4
12-4=8
A nutritional consulting company is trying to find what percentage of the population of a town is overweight. The marketing department of the company contacts by telephone 600 people from a list of the town's telephone directory. All 600 people give answers to the survey. Which of the following is the most significant source of bias in this survey?
a. Size of sample.
b. Undercoverage.
c. Voluntary response bias
d. Nonresponse.
e. Response bias.
Which situations can be simulated using this spinner? Select three options.
While on vacation in Lancaster, David went out for a dinner that cost $75. If sales tax in
Lancaster is 4% and David left a 20% tip on $75, what was the total cost of his meal?
Answer:
$93.
Step-by-step explanation:
Given that David went out for a dinner that cost $ 75, the price at which a sales tax of 4% was applied, and left a 20% tip on $ 75, to determine the total cost of his meal the following calculation must be performed:
75 + (75 x 0.2) + (75 x 0.04) = X
75 + 15 + 3 = X
93 = X
Therefore, the total cost he payed for his meal was $ 93.
Answer:
ok
Step-by-step explanation:
ok
i neeeeeeedddd helpppppppppp
Answer:
C.
Step-by-step explanation:
I honestly forget how to do this.
All credit goes to victoradisla08
HELP ME PLEASEEE ASAPPP
Select all the expressions that represent the area of the large, outer rectangle in figure A.
Please help quickly.
Answer:
Below three are the options
Step-by-step explanation:
6(3+2)
6*5
6.3+6.2
Answer:
6(3 + 2), 6 * 5, and 6 * 3 + 6 * 2 are all expressions that represent the area of the large outer rectangle in figure A.
Jamie is flying a kite at the beach. Jamie ties the string to a stake in the ground and
lets out 75 feet of string. If the angle of elevation of the kite is 55 degrees, how high is
the kite from the ground to the nearest foot?
Answer:
24
Step-by-step explanation:
that is what thinkof ur answer
Answer:
Height=61 feet
Step-by-step explanation:
Height=sin 55 degrees x 75
Height=0.8192 x 75
Height=61.43
4. A bicycle tire has a radius of 13 ¼ inches. How far will the bicycle travel in 40 rotations of the tire? Round to the nearest tenth
Answer:
It should be 530 inches, so 44 feet.
Step-by-step explanation:
I am not 100% but I did 13.25 times 40.
What is the value of y?
y =
At 12:00 a.m. the temperature was 0° F. By 4:00 a.m., the temperature dropped to five degrees
below zero.
Answer:
the temperature dropped 5 degrees in four hours
Step-by-step explanation:
find the values of x and y in the diagram
Answer:
y=2, x=3
Step-by-step explanation:
We can see that because triangle EHF has all 3 of the angles the same, EFH is an equilateral triangle and all of the sides are the same. So, we now know that y+2=4. if we simplify that, we find that y=2. Now, because the angles FHG and angle FGH are the same, triangle FHG is an isosceles triangle, and y+2=x+1. we now know that y+2=4, so x+1=4. simplify and x=3
I need help with this
Answer:
They multiplied by 100
Step-by-step explanation:
1 x 1.5 = 1.5
10 x 1.5 = 15
100 x 1.5 = 150
In 5 years, Nicole will
be old enough to vote in an election. The minimum age
for voting is at least 18 years. What can you say about
how old she is now? Write and solve an inequality to
show how old Nicole is now. Let a represent Nicole's
age now.
Answer:
Nicole is 13 years old because x + 5 = 18
Step-by-step explanation:
Whats the Quotient for 95÷5
Answer:
12
Step-by-step explanation:
Answer:
19
Step-by-step explanation:
I hope this helps you!
pls pls help me pls help me
Answer:
68m squared or the first option
Step-by-step explanation:
Find the sum
(3/8-1/6m+5t) + (7/10m+9t+1/4)
Answer:
5/8 +8/15m+ 14t
Step-by-step explanation:
Combine your like terms, and you will get this.
Thomas is saving money for a new mountain bike. The amount (a) Thomas needs to save is more than $50.45. Which inequality models the amount Thomas needs to save?
a > 550.45
<550.45
O $60.45 ca
50 45 = a
Answer:
its c
Step-by-step explanation:
This is because the amount is more than what he needs to save, considering that he is probably has some money in his bank already.