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PSYCHO15rus [73]
3 years ago
6

Write an expression to match the words three times the sum of 8 and 4

Mathematics
1 answer:
Eddi Din [679]3 years ago
8 0
3× (8+4)=
...............
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Samples of 20 parts from a metal punching process are selected every hour. Typically, 1% of the parts require rework. Let X deno
Roman55 [17]

Answer:

a) P(X>np+3\sqrt{np(1-p)}=0.017

b) P(x>1)=0.190

c) P(Y>1)=0.651

Step-by-step explanation:

This a binomial experiment where success is denoted by parts that need rework.

X ∼ B(n, p); n = 20; p = 0.01

The expected value of X is: E(X) = np =20×0.01= 0.2

The variance is: Var(X) = np(1 − p) = 0.2 × 0.99 = 0.198,

The standard deviation SD(X)= \sqrt{0.198} ≈ 0.445

a) P(X>np+3\sqrt{np(1-p)}=P(X>0.2+3×0.445)=P(X>1.535)=P(X≥2)

Probability function is given by:

\frac{n!}{x!(n-x)!} *p^x*(1-p)^{(n-x)}

P(X≥2)=1-P(X<2)=1-P(X=1)-P(X=0)= 1 - \frac{20!}{1!(20-1)!} *(0.01)^{1}*(1-0.01)^{(20-1)}-\frac{20!}{0!(20-0)!} *(0.01)^{0}*(1-0.01)^{(20-0)}

P(X≥2)=1-0.165-0.818=0.017

b) p=0.04

P(x>1)=P(x≥2)= 1 - P(x=1) - P(x=0)= 1 - \frac{20!}{0!(20-1)!} *(0.04)^{1}*(1-0.04)^{(20-1)} - \frac{20!}{0!(20-0)!} *(0.04)^{0}*(1-0.04)^{(20-0)}

P(x>1)= 1 - 0.368 - 0.442=0.190

c) In this case we consider p=0.19 (Probability that X exceeds 1)

In this experiment Y is the number of hours and n= 5 hours.

Then, we check the probability in each hour:

P(Y>1)=1- P(Y=0)

P(Y=0)=\frac{5!}{0!(5-0)!} *(0.19)^{0}*(1-0.19)^{(5-0)}=0.349

P(Y>1)=1-0.349=0.651

3 0
3 years ago
Using the key below, classify each of the following descriptions of epidemiologicalstudies according to study type. In your answ
emmasim [6.3K]

Answer:

Answers are written in BOLD in the explanation below.

Step-by-step explanation:

(A) The study was done in 1975 but the 825 insulation workers were employed or worked between 1941 and 1944. This makes the study a RETROSPECTIVE study.

There is an exposed group (insulation workers) and an unexposed group (coworkers who did not work with insulation). In addition (an additional reason), the study begins with exposed patients and then unexposed patients. These reasons make it a COHORT study.

This study is also an ANALYTICAL study, as the investigators made a postulation, based on analysis of the number of lung cancer deaths among non-insulation workers and the number of lung cancer deaths among insulation workers.

This is also an ECOLOGICAL study, as study results are applicable only at population level.

(B) This is an EXPERIMENTAL study, as the researcher/investigator seeks new knowledge by selecting groups to derive certain data from; in a step by step manner.

Due to the random selection of subjects (volunteers) and random assignment of them to the two groups, this is a RANDOMIZED TRIAL.

The presence of similar experimental and control groups (all volunteers/subjects have osteoarthritis) is a key feature of RANDOMIZED CONTROLLED TRIAL.

After the selection of subjects, experiment of pain levels was conducted for some months (up to a year). This makes the study a PROSPECTIVE study because there was follow-up on the groups, to see who develops the outcome of interest.

The fact that there was no experimental report after 9 and 12 months of follow-up is another key feature of the RCT because in a RCT, the investigator often faces issues like dropout and noncompliance of subjects.

(C) This is a COMMUNITY TRIAL study because two cities/communities are experimented on.

This is also an EXPERIMENTAL study. The fact that both cities have similar demographic profiles and air pollution levels confirms a key feature of experimental studies. There is a 2-year follow-up. This is another reason why the study is experimental and PROSPECTIVE.

(D) This is an OBSERVATIONAL study. This is because already available data was collected and simply looked upon or observed, to know if chewing tobacco was a significant risk factor for stomach cancer.

The data is historical data, hence this is a RETROSPECTIVE study.

This is also a CROSS-SECTIONAL study because it is observational in nature and it gives characteristics of subjects at a single point in time, not over a period of time. It does not have a follow-up period and cannot provide cause-effect relationship between variables.

GOODLUCK!

4 0
3 years ago
3 Select the correct answer. How can you write the expression 7(b – 2) in words? A. two subtracted from the quotient of seven di
aniked [119]

Answer:

E. the product of seven and the difference of b minus two

Step-by-step explanation:

7(b-2)

seven is being multiplied by the difference of b minus 2

So this can be written as the product of seven and the difference of b minus two.

Reasons its not the other answer choices

A. two subtracted from the quotient of seven divided by b would be (7/b) - 2

B. seven added to difference of b minus two would be 7 + (b-2)

C. the quotient of seven divided by b minus two would be 7/(b-2)

D. two subtracted from seven times b would be 7b - 2

Key Vocabulary:

<em>Difference = Subtraction</em>

<em>Product = Multiplication</em>

<em>Quotient = Division </em>

<em></em>

4 0
2 years ago
Read 2 more answers
Muffins are packed and sold in boxes of 4. How many boxes are needed to pack 260 muffins?
Volgvan

Answer:

65 boxes

Step-by-step explanation:

Im not sure how to explain other then say all you do is divide 260 and 4

I hope this helped!

Good luck!

If i did help maybe you could help me by giving me brainliest!?

Thanks! <3

5 0
3 years ago
5) Choose the inequality that will help solve the following situation: A jet ski rental charges a flat rate of $75, plus an addi
yanalaym [24]

Answer:

22.5

Step-by-step explanation:

You time 75 by 60. Then, you divided it by 200. The answer is 22.5.

Have A Good Day :)

7 0
3 years ago
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