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Dvinal [7]
3 years ago
15

Use the arithmetic sequence of numbers 1, 3, 5, 7, 9,.to find the following:

Mathematics
1 answer:
Rasek [7]3 years ago
6 0
a)\\\\
a_{n+1}-a_n=d\\
for\ n=1\\
a_2-a_1=d\\
d=3-1=2\ - difference\ between\ two\ consecutive\ terms\\\\
b)\\
a_n=a_1+(n-1)d\\
n=101\\
a_{101}=1+(101-1)*2\\
a_{101}=1+100*2=200+1=201\\\\
c)\\
Sn=\frac{a_1+a_n}{2}*n\\
n=20\\
a_n=a_{20}=1+(20-1)*2=1+38=39\\
Sn=\frac{1+39}{2}*20=400\ \ Sum\ of\ the\ first\ 20 \ numbers.
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30 points. Please help.
san4es73 [151]

Answer:

Good ways to sample

Simple random sample: Every member and set of members has an equal chance of being included in the sample. Technology, random number generators, or some other sort of chance process is needed to get a simple random sample.

Example—A teachers puts students' names in a hat and chooses without looking to get a sample of students.

Why it's good: Random samples are usually fairly representative since they don't favor certain members.

Stratified random sample: The population is first split into groups. The overall sample consists of some members from every group. The members from each group are chosen randomly.

Example—A student council surveys 100 students by getting random samples of 25 freshmen, 25 sophomores, 25 juniors, and 25 seniors.

Why it's good: A stratified sample guarantees that members from each group will be represented in the sample, so this sampling method is good when we want some members from every group.

Cluster random sample: The population is first split into groups. The overall sample consists of every member from some of the groups. The groups are selected at random.

Example—An airline company wants to survey its customers one day, so they randomly select 555 flights that day and survey every passenger on those flights.

Why it's good: A cluster sample gets every member from some of the groups, so it's good when each group reflects the population as a whole.

Example—A principal takes an alphabetized list of student names and picks a random starting point. Every 20th student is selected to take a survey.

Bad ways to sample

Convenience sample: The researcher chooses a sample that is readily available in some non-random way.

Example—A researcher polls people as they walk by on the street.

Why it's probably biased: The location and time of day and other factors may produce a biased sample of people.

Voluntary response sample: The researcher puts out a request for members of a population to join the sample, and people decide whether or not to be in the sample.

Example—A TV show host asks his viewers to visit his website and respond to an online poll.

Step-by-step explanation:

In a statistical study, sampling methods refer to how we select members from the population to be in the study.

If a sample isn't randomly selected, it will probably be biased in some way and the data may not be representative of the population.

There are many ways to select a sample—some good and some bad.

4 0
3 years ago
3(2-b) < 10-3(b-6) please help
Sonbull [250]
3(2-b)<10-3(b-6)
6-b<5(b-6)
6-b<5b-30
Let's make "b".......2
6-(2)<5(2)-30
4<10-30
4<-20
In this case, this is a false statement. You can make "b" any number and I chose 2. I hope this helped!
7 0
3 years ago
Read 2 more answers
Which set of numerical values represents the minimum, lower quartile, median, upper quartile, and maximum, in that order, of the
Nana76 [90]
51     53       55      58    60      so   the 4th one
7 0
3 years ago
Read 2 more answers
Find the period. Principal = 9300 =9300equals, 9300 rupees Annual rate of interest = 13 % =13%equals, 13, percent Total amount =
tekilochka [14]

Answer:

7 years

Step-by-step explanation:

Given:

Principal P = 9300

Interest rate r = 13% = 0.13

Final amount F = 17,763

Since the problem does not state that it is a compounded interest, we will assume this is a simple interest case.

The formula for simple interest is;

Interest I = Prt .....1

t = period

Final amount F = P + I

I = F-P

Substituting into equation 1;

(F-P) = Prt

t = (F-P)/Pr

Substituting the given values;

t = (17,763 - 9300)/(9300×0.13)

t = 7 years

Period = 7 years

5 0
3 years ago
Red Riding Hood is making a food basket out of 8 different fruits and 9 different vegetables. If there is only room for 6 items,
Bogdan [553]

Answer:

169,344

Step-by-step explanation:

Data provided in the question

Different fruits = 8

Different vegetables = 9

There is only room for 6 items

Based on the above information, the number of ways for an equal number of fruits & veggies is

For the number of combinations of fruit is

= 8\times7\times6

For the number of combinations of vegetables is

= 9\times8\times7

So, the total combinations are

= 9\times8\times8\times7\times7\times6

= 169,344

6 0
3 years ago
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