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Statistics
Statistics deals with collecting, organizing, and interpreting numerical data. An important aspect of statistics is the analysis of population characteristics inferred from sampling.
36,755 Questions
Is an arithmetic mean a weighted mean or a weighted mean an arithmetic mean?
The arithmetic mean is a weighted mean where each observation is given the same weight.
To calculate the probability of rolling an odd number on a die, you have a 3 out of 6 chance, as there are 3 odd numbers out of 6 sides. The probability of getting heads when tossing a coin is 1 out of 2. To find the probability of rolling an odd number OR getting a heads, you add the individual probabilities and subtract the overlap (rolling a 3, 5, or getting heads), resulting in a probability of 4 out of 6 or 2 out of 3.
What does consecrate or consecration mean?
Consecrate or consecration refers to the act of making something sacred or holy through a formal religious ritual or ceremony. It is often associated with dedicating a person, object, or space to a specific divine purpose or service. In Christianity, for example, consecration may involve the blessing of a church or the ordination of a priest.
How can you tell if a z score is unusual?
z scores are assumed to have come from a normal population with mean zero and standard deviation one. So the farther a z score deviates from the mean of zero the more significant, or unusual, it must be taken to be.
The measure of 'how significant' is the probability of getting a bigger z score.
For example, the probability of getting a z score bigger than 1.96 is about 0.025, the probability of getting one bigger that 3.5 about 0.000233.
Now the obvious problem is, how small is small? For a lot of scientific work either 0.05 is considered 'small enough'. Sometimes 0.01 is demanded. I notice that for recent Higg's boson work scientists have only accepted results associated with even smaller probabilities for some reason.
When you need to calculate probabilities such as these you can use published tables, or there are various kinds of software for desktop use. I have just used wolframalpha.com on the web with the following kind of input:
P[X<3.5] for X~normal with mean 0 standard deviation 1
(You will notice the z score of 3.5 in this expression.)
What are some words about Pennsylvania starting with x?
There is a street in Orefield, PA with the name Xmas Tree Drive.
A statistical anomaly occurs when something falls out of normal range for one group, but not as a result of being in that group.
For something less abstract: More members of Group A have a trait than members of Group B do, but members of Group B are just as capable of possessing that trait.
What is the median of 31 32 32 33 34 35 35 35?
The items are already in order, so you need to look for the middle value. In this case, with an even number (8) of items, you find the average of the middle two values:
(33+34)/2 = 67/2 = 33.5
What is the importance of statistics in information technology?
Statistics makes possible the prediction of particular outcomes, in a large general area of interest, inferred from the analysis of data gathered from a relatively small sample of that general area. Using inference, reliable information is indirectly obtained. This method is important, not only in information technology, but in many other areas as well. Statistics is a very efficient way to obtain and use information
What are the main qualities of a good estimator?
A "Good" estimator is the one which provides an estimate with the following qualities:
Unbiasedness: An estimate is said to be an unbiased estimate of a given parameter when the expected value of that estimator can be shown to be equal to the parameter being estimated. For example, the mean of a sample is an unbiased estimate of the mean of the population from which the sample was drawn. Unbiasedness is a good quality for an estimate, since, in such a case, using weighted average of several estimates provides a better estimate than each one of those estimates. Therefore, unbiasedness allows us to upgrade our estimates. For example, if your estimates of the population mean µ are say, 10, and 11.2 from two independent samples of sizes 20, and 30 respectively, then a better estimate of the population mean µ based on both samples is [20 (10) + 30 (11.2)] (20 + 30) = 10.75.
Consistency: The standard deviation of an estimate is called the standard error of that estimate. The larger the standard error the more error in your estimate. The standard deviation of an estimate is a commonly used index of the error entailed in estimating a population parameter based on the information in a random sample of size n from the entire population.
An estimator is said to be "consistent" if increasing the sample size produces an estimate with smaller standard error. Therefore, your estimate is "consistent" with the sample size. That is, spending more money to obtain a larger sample produces a better estimate.
Efficiency: An efficient estimate is one which has the smallest standard error among all unbiased estimators.
The "best" estimator is the one which is the closest to the population parameter being estimated.
What is the method used to demonstrate a cause and effect relationship between two variables?
Statistically, you would need to conduct an experiment in which every single other variable was controlled. Not a feasible option so you control the obvious covariates and examine the residual covariance between the two variables of interest.
Even so, you may not find something. For example, the covariance between x and y where y= x2 over any symmetric interval is 0.
What are all the possible 11 digit combinations of letters A-Z and numbers 0-9 combined?
There are 36 possible characters (26 letters + 10 numbers) that can be used in each position of the 11-digit combination. Therefore, the total number of possible combinations is 36^11, which is approximately 7.52 x 10^17. This means there are over 750 quadrillion possible 11-digit combinations of letters A-Z and numbers 0-9 when combined.
Ralph likes 25 but not 24 he likes 400 but not 300 he likes 144 but not 145 Why does he like 200?
Well, isn't that just a happy little riddle! Ralph likes numbers that are perfect squares, like 25, 400, and 144. Since 200 is also a perfect square (200 x 200 = 40,000), that's why Ralph likes it too. Just like painting, sometimes things just fit together perfectly!
Well, darling, if you want a 4-digit combination with no repeated numbers using 0-9, you simply multiply the number of choices for each digit. So, for the first digit, you have 10 options, then 9 for the second (can't repeat the first digit), 8 for the third, and 7 for the fourth. Multiply those together and you get 10 x 9 x 8 x 7 = 5040 unique combinations. Hope that tickles your fancy!
How many 3 digit numbers can be made using 3 6 and 9 if digits can be repeated?
Well, honey, if you're using 3, 6, and 9 to make a 3-digit number with repetition allowed, you've got 3 choices for each digit. So that's 3 choices for the hundreds place, 3 choices for the tens place, and 3 choices for the units place. Multiply those together and you get 3 x 3 x 3, which equals 27 possible 3-digit numbers. Math made sassy!
If there are more than one class intervals which have the same frequency (equally qualifying to be the mode class) then both of the classes will be the mode class. this is called bimodal.
However to calculate the mode of grouped data use the following formula
Mode = L + [ (F - F1) / { (F - F1) + (F - F2) } ] * h
where
L = Lower limit of the modal class
F = Frequency of the modal class
F1 = Frequency of the class immediately previous of modal class
F2 = Frequency of the class immediate next of modal class
h = Range of the modal class (higher limit - lower limit)
this is what i found out after reading books and understanding them. Please correct me if i am wrong.
Thanks,
Salman Ahmad
What is the difference between a whole 1 and three tenths?
1 is the whole number a whole broken in to tenths is 10 10 tenths (10/10)
Therefore 3/10 (three tenths) is 3 parts of the whole amount
What is a 400 digit number called?
A 400-digit number is typically referred to as a "400-digit number." In mathematics, numbers are categorized by their number of digits, such as single-digit numbers, double-digit numbers, triple-digit numbers, and so on. Therefore, a number with 400 digits would simply be called a "400-digit number."
What do you do if there is 2 median?
In a odd set of numbers the middle number is the median, but if there's a even set of numbers, say 6 for example, you add the two numbers in the middle then divide them by 2 and you will end up with the middle of the two middle numbers- what a mouthful! Or another way to do it is if the two middle numbers are say 4 and 6 then obviously the number between them is 5
Example: Find the median for these numbers.
2,3,4,5,6,7
4+5=9
9 divided by 2=4.5
Therefore the answer is 4.5
What does it mean when the display on a treadmill reads that the distance is .82?
Oh, dude, that's just fancy talk for saying you've run or walked 0.82 miles. It's like telling you, "Hey, you've almost made it to that coffee shop down the street, but not quite." So, you're almost there, just keep going, or, you know, take a break and grab a latte.
What shapes has two right angles?
Ah, a shape with two right angles is called a rectangle, my friend. It's a wonderful and balanced shape that can be found all around us in everyday objects. Remember, every shape is unique and special in its own way, just like you are.
How many combinations can you get with 8 numbers in a seven number combination?
8x7x6x5x4x3x2 or 40320
* * * * *
That is totally incorrect. There are only 8 combinations: one with each of the 8 numbers missing. In a combination the order does not matter so 1234567 is the same as 1236547 or 7643125 etc.
How many different 5 number combinations can you make with 35 numbers?
The number of combinations of 35 things taken 5 at a time is 35! / (5! * (35-5)! which is 35! / (5! * 30!). 35! / 30! is 35 * 34 * 33 * 32 * 31, and 5! is 120. After cancelling we are left with 7 * 34 * 11 * 4 * 31 which is 324,632
