-
Anonymous users2024-02-06High school math elective 2-3 independence test, you can go to the textbook.
The following is an excerpt from the encyclopedia independence test, a test method of statistics. It belongs to the X2 test (chi-square test, English name: chi square test) and is a hypothesis test that judges that two types of factors are related or independent of each other based on the number of data.
Suppose there are two categorical variables x and y, and their ranges are divided into sums, and their sample frequency contingency table is:
y1y2 total x1ABA+BX2CDc+D total a+cb+da+b+c+d
If we want to infer the argument h1: "x is related to y", we can use the independence test to examine whether the two variables are related, and we can give a more accurate degree of reliability for this judgment. Specifically, the value of the random variable k 2 (i.e., the square of k) is calculated from the data in the table: k 2 = n (ad - bc) 2 [(a+b)(c+d)(a+c)(b+d)] where n=a+b+c+d is the sample size k2, the greater the probability that "x is related to y" is true.
When the data a, b, c, and d in the table are not less than 5, the following table can be consulted to determine the degree of credibility of the conclusion that "x is related to y".
p(k2k) For example, when the value of the k2 variable of "x is related to y" is , according to **, because of the <, the probability that "x is related to y" is true, i.e. According to the above theory, the calculation is sufficient.
-
Anonymous users2024-02-05Critical value, fixed to determine independence.
-
Anonymous users2024-02-04(1) Substituting y=x+m into 4x 2+y 2=1 to get 5x 2+2mx+m 2-1=0, 4m 2-4*5 (m 2-1)" 0=>-root number 5 2 "x "root number 5 2.".Let y (x+2)=k=>y=kx+2k substitute into the elliptic equation to obtain (k 2+4) x 2+4k 2x+4k 2-1=0=>16k 4-4(k 2+4)(4k 2-1)" 0=>-2 root number 15 15 "k "2 root number 15 15
-
Anonymous users2024-02-03Equal difference series, so.
a m-1 + a m+1= 2 am
So. 2am-am^2=0
am=0 or 2
First of all, you have to adjust your mentality, don't be afraid of math, I'm a sophomore in high school, I'm your age, I'm a math master. In fact, I am not a strong player, and my math learning is not top-notch, but I pay attention to my own weaknesses, practice more of my weak question types, and summarize methods. In fact, you should not take the test attitude to learn mathematics, which will make you feel pressured to enjoy the infinite fun that the mystery of mathematics brings you. >>>More
By the question, there is |f(-1)|= |-a+b|<=1 ; f(1)|= |a+b| <=1 >>>More
Absolutely. As long as you meet the requirements for studying abroad, you can choose a school to enroll.
Every year, when the sun reaches 270 degrees of ecliptic longitude, it is the winter solstice in the 24 solar terms. The winter solstice, also known as the winter festival or the winter of Hedong, is the opposite of the summer solstice, and is one of the eight celestial solar terms in the 24 solar terms. So do you know what day the winter solstice is in 2018? >>>More
Talk to your teacher. You must know that the teacher has also experienced high school, but because it has been too long since he forgot about the "sorrows" like you said, communication is the best way. Specifically, after class, when you feel that he has time, you can use asking questions as an "excuse" to take the opportunity to talk about your feelings about his class and other aspects, and by the way, to discuss his understanding of you. >>>More