Answer:
The disadvantages: Convenience samples do not produce representative results. If you need to extrapolate to the target population, convenience samples aren't going to get you there. ... Much larger convenience samples are not more accurate than small probability samples.
Which one is the answer
Fred earns $ 45 mowing the lawn. He spends $ 5 on music, and puts half of what's left in a savings account. He then gets another $ 10 for washing his neighbor's car. First, write the expression that represents the number of dollars Fred keeps (and does not put in his savings account), and then simplify.
Answer:
$30
Step-by-step explanation:
Given that :
Amount earned for mowing = $45
Amount spent on music = $5
Amount earned for washing neighbor's car = $10
Amount saved = half or remaining amount
Amount of dollars Fred keeps =
Amount Fred keeps:
[(Amount earned - amount spent) / 2] + $10
[($45 - $5) / 2] +
($40 / 2) + $10
= $20 + $10
= $30
A chemist examines 17 sedimentary samples for lead concentration. The mean lead concentration for the sample data is 0.268 cc/cubic meter with a standard deviation of 0.069. Determine the 80% confidence interval for the population mean lead concentration. Assume the population is approximately normal. Step 1 of 2 : Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.
Answer:
The critical value that should be used in constructing the confidence interval is T = 1.337.
The 80% confidence interval for the population mean lead concentration is between 0.246 and 0.29 cc/cubic meter.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution 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 = 17 - 1 = 16
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 16 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.8}{2} = 0.9[/tex]. So we have T = 1.337, which is the crical value.
The margin of error is:
[tex]M = T\frac{s}{\sqrt{n}} = 1.337\frac{0.069}{\sqrt{17}} = 0.022[/tex]
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 0.268 - 0.022 = 0.246 cc/cubic meter
The upper end of the interval is the sample mean added to M. So it is 0.268 + 0.022 = 0.29 cc/cubic meter
The 80% confidence interval for the population mean lead concentration is between 0.246 and 0.29 cc/cubic meter
The probability that it will rain tomorrow is 0.65
What is the probability that it will not rain tomorrow?
Answer:
.35%
Step-by-step explanation:
100% - .65% = .35%
and sorry for asking but, if this is right could i please get a thanks & brainliest recently a moderator deleted ALL my answers (over 400 answers) causing me to lose over 3k points so id appreciate it alot thanks xoxo
9a + 18c. What is the value of the expression when a = −5 and c = −1?
Bao has two summer jobs. During the week she works in the grocery store,
and on the weekend she works at a nursery. She gets paid $19 per hour to
work at the grocery store and $20 per hour to work at the nursery. How much
does she earn if she works 6 hours at the grocery store and 10 hours at the
nursery? How much does she earn if she works g hours at the grocery store
and n hours at the nursery?
Answer:
She gets $114 to work at grocery store for 6 hours and $200 at the nursery.
Answer: $294
20g+19
Step-by-step explanation:
20*9=180
19*6=114
180+114=294
Find the measure of <2!
Answer fast pls, 15 pts! <3
Answer:
65
Step-by-step explanation:
180-115=65
It needs to be a total of 180 so just do what I did :)
The sum of two numbers is 70. The difference of the two numbers is 32. What are the two numbers.
51 + 19 = 70
51 - 19 = 32
hope that helped!!
Answer:
51 and 19
Step-by-step explanation:
Carlos bought a new computer printer for $110.50 and some ink cartridges
for $8.25 each. He spent a total of $176.50.
The equation $176.50 = $110.50 + $8.25c can be used to solve this
problem. Which two mathematical operations do you need to perform in
order to solve the equation for c?
A. addition and multiplication
B. division and multiplication
C. subtraction and division
D. multiplication and subtraction
help pls i need this asap
Help please and thanks
Answer:
option A
Step-by-step explanation:
plz mark my answer as brainlist plzzzz . hope this will be helpful to you.
In the diagram below AB is parallel to CD . What is the value of x ?
Can you look at the photo and help please.?
Answer:
sorry it aint werking for meeee
Step-by-step explanation:
1 is what % of 200 ?
Answer:
1 is 0.5% of 200
Hope it helped u,
pls mark as the brainliest
^_^
Michael works 30 hours per week and makes $15.00 per hour. How much does he make in a 4-week month?
Answer:
$1,800
Step-by-step explanation:
If Michael works 30 hours a week for $15 an hour we can use the equation:
15 x 30 = 450.
Now just multiply the given answer by 4 and you're left with:
450 x 4 = 1800.
Evaluate the geometric series below. Please show your work.
Answer:
-1310715
Step-by-step explanation:
By the formula of a geometric sequence, we work out:
[tex]\sum_{k=1}^{18} -5 \cdot 2^{k-1}\\= -5 \cdot \sum_{k=0}^{17} 2^{k}\\= -5 \cdot \frac{2^{18}-1}{2-1}\\= -1310715[/tex]
4x(x2-4x+5)-2x2(2x2-8x-1)
NEED HELP ASAP!!!Of all the students who tried out for volleyball, 83% made the team what fraction of the students who tried out did NOT make the team?
Answers
4/5
1/5
3/4
1/3
Answer:I think it’s 1/5 but if u have another attemp and it’s wrong somehow do 1/3
Step-by-step explanation:
Answer:
3/4 or 1/3
Step-by-step explanation:
The ratio of boys to girls is 2 to 3. There are 10 boys. How many girls are in the club?
Answer:
15 girls.
Step-by-step explanation:
Hope this helps!
Answer:
15 girls
Step-by-step explanation:
2:3 ratio
If you know the amount of boys, then 2x=10, x=5
Now you know that the scale factor is 5
So, multiply 5*3 to get the amount of girls
Please answer with explanation, I don't understand.
[tex]\sqrt{x^2-14x+49} =x-7[/tex]
Answer: x ≥ 7
Step-by-step explanation:
You have to square both sides of the equation. You can manipulate an equation or function any way imaginable as long as it is done equally and helps the problem become easier. If we square this, the radical will cancel and we will get two trinomials equal to each other.
[tex]x^2-14x+49=(x-7)^2\\x^2-14x+49=x^2-14x+49[/tex]
We can see the two expressions are exactly equal to each other. All real numbers are solutions, besides a few. These few are when the radical is equal to a negative number. So lets set up an inequality stating that the radical must be greater than or equal to 0.
[tex]x^2-14x+49\geq 0\\(x-7)^2 \geq 0\\x \geq 7[/tex]
Chris works at a jewelry store, and he earns 4% commission on all sales that he makes. If Chris's jewelry sales total $1,370, how much will he earn in commission?
Leanna is making a craft and needs 12 yards of ribbon. If 2 yards of ribbon cost $1.25, how much will 12 yards cost?
Answer:
$7.50
Step-by-step explanation:
2 yd= 1.25
we have 12 yd so 12/2= 6
6*1.25= 7.50
Approximate 589.57 to the nearest whole number..
Answer:
590.00
Step-by-step explanation:
Im guessing SORRY
Explain what is wrong with each of the following randomization procedures, and describe how you would do the randomization correctly.
a. Twenty students are to be used to evaluate a new treatment. Ten men are assigned to receive the treatment, and 10 women are assigned to be the controls.
b. Ten subjects are to be assigned to two treatments, 5 to each. For each subject, a coin is tossed. If the coin comes up heads, the subject is assigned to the first treatment: if the coin comes up tails, the subject is assigned to the second treatment.
c. An experiment will assign 40 rats to four different treatment conditions. The rats arrive from the supplier in batches of 10, and the treatment lasts two weeks. The first batch of 10 rats is randomly assigned to one of the four treatments, and data for these rats are collected. After a one-week break, another batch of 10 rats arrives and is assigned to one of the three remaining treatments. The process continues until the last batch of rats is given the treatment that has not been assigned to the three previous batches.
Answer:
Kindly check explanation
Step-by-step explanation:
A.)
The problem with the here is that we might have introduced bias into our sample by failing to randomize the assignment of gender. By pacing the male gender in the treatment group and females into the control group, this might spring up a spurious association in our experiment as a result of a possible confounding variable, gender. Therefore, assignment of subject shouldn't be on the basis of gender.
2.)
Using a coin toss in placing subjects into groups will give a good random assignment, however, since only ten subjects are available and of which 5 will be placed into each group, there is no certainty that there will be equal number of heads and tails during the 10 flips. Alternatively, a random selection of the name of the 10 subjects could be chosen from a raffle.
3.)
Each batch of rat might be homogenous and hence will affect our experiment and definitely our conclusion. It would be best to assign rats from each batch to all treatment groups in other to obtain a good random design
what is the value of v
Answer:
43
Step-by-step explanation:
v+47 is equal to 90 degrees, because it's a right angle
v+47=90
to get 90 in this equation, v must equal 43.
that means v=43
after 4 new students joined a class,the class had 32 students.Which equation can be used to find n,the number of students in the class before the 4 new students joined
Find a. Give your answer in
the simplest form.
[?]
a
zva
d
а
45
30
b
с
Answer:
a=7
Step-by-step explanation:
7(sq rt 2)=(sq rt 98)
sin 45=a/(sq rt 98)
0.7071=a/(sq rt 98)
a=0.7071(sq rt 98)
a=7
Which lists the fractions 4/7,5/9,and 2/3 in order from least to greatest?
Pls I need for both
Answer:
slope=(3--5)/(7--4)=8/11
Step-by-step explanation:
slope=(3-4)/(10-8)=-1/2
How to find the Perimeter?
Answer:
8+2[tex]\sqrt{20\\}\\[/tex]
Step-by-step explanation:
2+2+2+2+[tex]\sqrt{20\\}\\[/tex]+[tex]\sqrt{20\\}\\[/tex]=8+2[tex]\sqrt{20\\}\\[/tex]
4^2+2^2=h^2
20=h^2
h=[tex]\sqrt{20\\}\\[/tex]