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STATISTICS AND PROBABILITY
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Statistics and Probability Answers
Probability
asked 2021-03-12
A statistical investigation showed that adults in a particular country have an 80% chance of living to be at least 70 years old and a 50% chance of living to be at least 80 years old. What is the probability that an adult who just turned 70 will live to be 80?
Probability
asked 2021-03-11
Three students are arguing, Chad says, "I think the probability is 1 out of 2." Tien says, "No, it is 40 over 80." Falicia says, "It is 50%." What do you say to the students?
Normal distributions
asked 2021-03-11
Consider two independent populations that are normally distributions. A simple random sample of
\(\displaystyle{n}_{{1}}={41}\)
from the first population showed
\(\displaystyle\overline{{x}}_{{11}}={33}\)
, and a simple random of size
\(\displaystyle{n}_{{2}}={48}\)
from the second population showed
\(\displaystyle\overline{{x}}_{{2}}={32}\)
Suppose
\(\displaystyle{s}_{{1}}={9}{s}_{{1}}={9}{\quad\text{and}\quad}{s}_{{2}}={10}{s}_{{2}}={10}\)
, find a 98% confidence interval for
\(\displaystyle\mu_{{1}}−\mu_{{2}}\mu_{{1}}-\mu_{{2}}\)
. (Round answers to two decimal places.)
margin of error-?
lower limit-?
upper limit-?
Data distributions
asked 2021-03-11
What is the difference between a normal profile of a random variable and normal pdf of a random variable.
Study design
asked 2021-03-11
To find:Whether the experiment is an observational or a designed experiment.
Study design
asked 2021-03-09
A proposed study design is to leave 100 questionnaires by the checkout line in a student cafeteria. The questionnaire can be picked up by any student and returned to the cashier. Explain why this volunteer sample is a poor study design.
Two-way tables
asked 2021-03-08
Using data from the 2000 census, a random sample of 348 U.S. residents aged 18 and older was selected. The two-way table summarizes the relationship between marital status and housing status for these residents.
\(\displaystyle{b}{e}{g}\in{\left\lbrace{a}{r}{r}{a}{y}\right\rbrace}{\left\lbrace{l}{\left|{c}\right|}{c}{\mid}{c}\right\rbrace}&{M}{a}{r}{r}{i}{e}{d}&{N}{o}{t}{m}{a}{r}{r}{i}{e}{d}&{T}{o}{t}{a}{l}\backslash{h}{l}\in{e}{O}{w}{n}&{172}&{82}&{254}\backslash{h}{l}\in{e}{R}{e}{n}{t}&{40}&{54}&{94}\backslash{h}{l}\in{e}{T}{o}{t}{a}{l}&{212}&{136}&{348}{e}{n}{d}{\left\lbrace{a}{r}{r}{a}{y}\right\rbrace}\)
Scatterplots
asked 2021-03-08
A nutritionist collects the weight of college students in the first semester, then again in the second semester. What is the best way to visually present this data?
a) Line Graphs
b) Scatterplots
c) Bar Graphs
d) Pie Charts
Normal distributions
asked 2021-03-08
Explain some of the important characteristics of a normal distribution.
Data distributions
asked 2021-03-07
We have a set of n-elements (A), and a set of m-elements (B).
\(\displaystyle{n}\ge{0}\)
\(\displaystyle{m}\ge{0}\)
Find how many relations there're from A to B.
Probability
asked 2021-03-07
A hip joint replacement part is being stress-tested in a laboratory. The probability of successfully completing the test is 0.883. 11 randomly and independently chosen parts are tested. What is the probability that exactly two of the 11 parts successfully complete the test?
Binomial probability
asked 2021-03-06
When dealing with the binomial distribution, why are the possible values for the random variable always 0,1,2,3,…,n where n is the number of trials or sample size? Why can't we use negative values, or fractions, or numbers greater than n?
Scatterplots
asked 2021-03-06
Make a scatterplot for the data.
Height and Weight of Females
Height (in.): 58, 60, 62, 64, 65, 66, 68, 70, 72
Weight (lb): 115, 120, 125, 133, 136, 115, 146, 153, 159
Normal distributions
asked 2021-03-06
A normal distribution has
\(\mu = 30\)
and
\(\sigma = 5\)
.
(c)Find the raw score corresponding to
\(z =-2\)
.
Probability
asked 2021-03-05
You ask a neighbor to water a sickly plant while you are on vacation. Without water the plant will die with probability 0.85. With water it will die with probability 0.5. You are 90 % certain the neighbor will remember to water the plant. You come back from the vacation and the plant is dead. What is the probability that the plant died because neighbor forgot to water it?
Probability
asked 2021-03-05
[Graph]
P(red or yellow) 30%
P(not green)
Scatterplots
asked 2021-03-05
Match the values of r with the accompanying scatterplots 0.723,-0.353,0.353,0.998 and -0.998
scatterplots 1,2,3,4,5
Two-way tables
asked 2021-03-05
1950 randomly selected adults were asked if they think they are financially better off than their parents. The following table gives the two-way classification of the responses based on the education levels of the persons included in the survey and whether they are financially better off, the same as, or worse off than their parents
\(\begin{array}{|c|c|c|}\hline &\text{Less Than High School}&\text{High School}&\text{More Than High School}\\\hline \text{Better off} &140&440&430\\ \hline \text{Same as}&60&230&110\\ \hline \text{Worse off}&180&280&80\\ \hline\end{array}\\\)
Suppose one adult is selected at random from these 1950 adults. Find the following probablity.
Round your answer to three decimal places.
\(P(\text{more than high school or worse off})=?\)
Scatterplots
asked 2021-03-04
Sketch a scatterplot where the association is linear, but the correlation is close to [r = 0].
Normal distributions
asked 2021-03-04
Consider the marks of all 1st-year students on a statistics test. If the marks have a normal distribution with a mean of 72 and a standard deviation of 9, then the probability that a random sample of 10 students from this group have a sample mean between 71 and 73 is?
1
2
3
4
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17
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