Statistics Homework Answers & Questions

Waiting for answer Is a bell curve symmetric, rightskewed, or leftskewed?
Normal (commonly referred to as bell) curves are symmetric, because if you draw a line vertically through the mean of the distribution there is as much of the distribution on the left as there is on the right. If a distribution has more of the observations on the left side of the mean it is calle...
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Waiting for answer Permutation and combination? In your own words, explain the...
See explanation. Permutation of a set is a sequence in which the order is important (it means that for example ##135## and ##153## are two different permutations of a set ##{1,3,5}#...
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Waiting for answer A coin is flipped 12 times. What is the probability of getti...
##495/4096## The number of possible sequences of heads and tails in ##12## coin tosses is: ##2^12 = 4096## The number of ways that such a sequence could contain exactly ##8## hea...
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Waiting for answer What are independent trials, and how do they relate to the d...
In Probability we use the term Bernoullian trials for independent trials. A sequence of trials are said to be Bernoullian if (i) there are only two outcomes for each trial ( say a su...
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Waiting for answer How do you find the cumulative relative frequency?
It's a matter of adding up and taking percentages If you have a frequency table, you add a few columns to your table: Cumulative frequency Relative frequency Cumulative relative frequency Cumulative frequency You add the frequencies up to and including for the value Relative frequency You...
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Waiting for answer How do you find the central angle of a pie chart for a secti...
Each pie chart has 360°, since it is represented by a complete circle. If you are looking for 20% of that circle, you will use 20% of its 360 degrees as well. ##20/100 *360° = 72°## Or: You can say: ##100% hArr 360^0## so every ##1% hArr3.6^0## and work from there.
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Waiting for answer What is a voluntary response sample?
In survey sampling, voluntary response bias occurs when sample members are selfselected volunteers, as in voluntary samples . An example would be callin radio shows that solicit audience participation in surveys on controversial topics (abortion, affirmative action, gun control, etc.). An example...
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Waiting for answer What is a z score in regard to relative position?
Hi! A Zscore measures the "relative distance" of an observation in terms of standard deviations, from the mean. It gives an idea as to how far the observation is from its mean. A positive zscore indicates that the observation is above the mean and a negative value indicates that the observation is...
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Waiting for answer Suppose that X is a discrete random variable with probabilit...
##c = 10/3## ##E(x) = sum x* P(x)## Properties of p.d.f. include ##sump(x) = 1## ##sum P(x) = 1 ## = ## c[1 +4 + 9 + 16 ] = 1 ## = ##30c = 1 ## = ## c = 1/30.E(x) ## ## =...
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Waiting for answer What are "p hat" and "p"?
p is the population measure of the proportion, equal to X/N. it is called a parameter. phat is an estimate of p (above) derived from a finite sample, equal to x/n. it is called a statistic, normally written as ##hat p##
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Waiting for answer What is a uniform density curve?
The density curve for a probability distribution is its graphical representation. The area under a density curve is always equal to 1. The Uniform distribution has equal probabilities for all possible values in its range, so the Uniform density curve is just a horizontal line, running from the lowe...
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Waiting for answer How do you calculate sample mean?
Sample mean is the arithmetic average of all the observations in a particular sample. Sample mean is the estimator of population mean. Given a sample of size n, X1, X2, ..... ,Xn are the observations, then the sample mean is calculated as the summation of all Xi divided by n. In symbols x̅ =...
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Waiting for answer How do you calculate critical value chi squared?
The chisquare statistic is used to compare two categorical variables to see if they are related. Calculating the statistic involves looking the figure up in the chisquare table. w...
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Waiting for answer How do you find the mean, median, mode and range of 30, 34,...
See explanation. First thing we need tio do is to put the data in increasing order. This is needed to calculate the median: ##30,31,32,33,34,35,35,36,37,39## Now we can calculate t...
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Waiting for answer If a person scores in the 45th percentile on the ACT, how do...
It means that about 45% of the people did worse, and about 55% did better. You can 'carve up' your population according to score. You probably now the term median , which is the value of the middle of your population (when arranged by value). Quartiles are also widely used, they divide the (ordere...
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Waiting for answer What does a negative correlation coefficient mean about a sc...
A negative correlation means that there is an inverse relationship between two variables. A negative correlation means that there is an inverse relationship between two variables. T...
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Waiting for answer A card is drawn from a standard deck of 52 playing cards. Wh...
##2/13## There are 52 cards in a standard deck: 13 ordinal cards (Ace  10, Jack, Queen, King) and 4 of them  one to each suit (hearts, diamonds, clubs, spades) and so we have ##4xx...
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Waiting for answer What is the average deviation of ##1.76, 2.28, 1.90##?
mean deviation ##=0.2## Compute mean ##barx## ##barx=(1.76+2.28+1.90)/3=1.98## Mean deviation ##=(sum abs(xbarx))/n## Mean deviation ##=(abs(1.761.98)+abs(2.281.98)+abs(1.901....
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Waiting for answer What is the formula for calculating the test statistic for a...
Is it onepopulation z test? Because we cannot have one sample only in stat experiments. In z test, it is preferable to have n = 30. We have the formula, z= (computed mean  hypothesized mean) divided by the standard error. SE(standard error) = standard deviation/n.
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Waiting for answer A sock drawer has 8 blue socks and 6 black socks. If I rando...
##24/91## Calculate first the total number of permutation possible. You select two socks so that will be: ##14*13=182## Now you must first select a blue sock then a black sock: Y...
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